The Ogham Alphabet: Meanings of All 20 Celtic Tree Letters

The Ogham is an alphabet written in trees. Each of its twenty letters is named for a tree or plant, and each carries a body of wisdom, lore, and spiritual meaning that has accumulated over centuries. To learn the Ogham is to learn a language of the forest, a system of knowledge so deeply rooted in the natural world that studying it changes your relationship with every tree you encounter.

This guide explores all twenty letters of the core Ogham alphabet in detail, offering their names, associated trees, divinatory meanings, and the spiritual qualities they carry. The Ogham rewards deep, sustained study. These are not symbols to be memorized in an afternoon. They are teachers to be visited again and again, each visit revealing another layer.

Understanding the Ogham Structure

The twenty letters of the Ogham are divided into four groups of five called aicmi (the plural of aicme, meaning "family" or "group"). Each aicme contains five letters represented by one to five straight lines carved on one side of, across, or on the other side of a central vertical line called the druim or "spine."

The four aicmi are:

• First Aicme (B group): Beith, Luis, Fearn, Saille, Nuin -- lines to the right of the druim
• Second Aicme (H group): Huath, Duir, Tinne, Coll, Quert -- lines to the left of the druim
• Third Aicme (M group): Muin, Gort, nGetal, Straif, Ruis -- lines crossing the druim diagonally
• Fourth Aicme (A group): Ailm, Onn, Ur, Eadha, Ioho -- lines crossing the druim horizontally or as notches

A fifth group of five letters, called the Forfeda, was added later and is sometimes used in modern practice. This guide focuses on the original twenty.

First Aicme: The Foundation

Beith -- Birch

Letter: B Tree: Birch (Betula) Season: Late December to late January Color: White Bird: Pheasant

Birch is the pioneer. It is the first tree in the Ogham because it is the first tree to appear on bare ground, the harbinger of the forest that will follow. Its bark is papery and white, luminous against the dark earth and winter sky. Birch grows fast, lives relatively briefly for a tree, and puts all its energy into colonizing new territory.

When Beith appears in a reading, something new is beginning. The old ground has been cleared, whether by your choice or by circumstances beyond your control, and the first tender shoot of what comes next is pushing through. Beith asks you to embrace the fresh start without clinging to what was. Purify. Simplify. Let go of accumulated clutter, whether physical, emotional, or mental. Birch sweeps clean.

In spiritual practice: Beith is the energy of initiation, the first step on a new path. When you feel the stirring of a new direction but have not yet taken action, you are in Beith's territory. Honor it by actually beginning, however small the first step.

Luis -- Rowan

Letter: L Tree: Rowan (Sorbus aucuparia) Season: Late January to late February Color: Grey or red Bird: Duck

Rowan is the protector. Its clusters of bright red berries, each one bearing a tiny pentagram at its base, were carried as charms against harmful enchantment throughout the Celtic world. Rowan was planted at the corners of fields and beside doorways to guard the household against malevolent forces.

Luis in a reading speaks to your ability to see through illusion and protect yourself from deception, whether external or self-generated. It is a call to sharpen your discernment, to distinguish between what is genuinely nourishing and what merely looks appealing, between authentic spiritual guidance and glamorous distraction.

In spiritual practice: Luis is the guardian of your inner truth. When you feel confused, manipulated, or unsure of what to trust, call upon rowan's clarity. Its medicine is the ability to see what is real.

Fearn -- Alder

Letter: F (V) Tree: Alder (Alnus glutinosa) Season: Late February to late March Color: Crimson Bird: Gull

Alder is the bridge-builder. It thrives with its roots submerged in water, standing at the boundary between land and stream, between the solid and the flowing. When alder wood is cut, it turns from white to blood-red, a transformation that gave it associations with warrior courage and the willingness to confront.

Fearn in a reading asks you to stand firm at the boundary, to hold your ground in fluid and uncertain circumstances. It is the energy of courage applied to emotional territory: the willingness to enter difficult feelings, to wade into the waters that others avoid, and to build bridges between opposing forces.

In spiritual practice: Fearn appears when you are called to confront something you have been avoiding, usually something emotional or relational. It gives you the courage to step into the water and the stability to remain standing once you are there.

Saille -- Willow

Letter: S Tree: Willow (Salix) Season: Late March to late April Color: Silver or bright Bird: Hawk

Willow is the moon tree, the tree of water, intuition, and the deep feminine. Its long, flexible branches trail into rivers and streams, drawing up the moisture of the emotional realm. Willow bends in storms that snap stronger-seeming trees. Its strength is the strength of yielding.

Saille in a reading invites you to trust your intuition, to follow the guidance that comes through feeling and dreaming rather than thinking and analyzing. It is also a reminder to be flexible. Rigidity will break you. Flexibility will carry you through.

In spiritual practice: Saille governs the lunar, receptive, intuitive aspect of your being. When logic fails and analysis exhausts, willow medicine offers an alternative way of knowing: through the body, through dreams, through the quiet voice that speaks only when the rational mind is still.

Nuin -- Ash

Letter: N Tree: Ash (Fraxinus excelsior) Season: Late April to late May Color: Glass green or clear Bird: Snipe

Ash is the World Tree. In Norse tradition, the great ash Yggdrasil connects all nine worlds. In Celtic tradition, ash links the three realms of land, sea, and sky. It is the tree of interconnection, the cosmic axis, the living proof that everything is connected to everything else.

Nuin in a reading reveals the larger web of which your current situation is a part. It asks you to zoom out and see how your individual experience connects to family patterns, community dynamics, and universal themes. Nothing exists in isolation, and Nuin reminds you that the thread you are pulling is attached to a vast tapestry.

In spiritual practice: Nuin is the energy of linking, of seeing connections that were previously invisible. Meditation with ash opens your awareness to the web of relationships that holds your life in place.

Second Aicme: The Deepening

Huath -- Hawthorn

Letter: H Tree: Hawthorn (Crataegus) Season: Late May to mid-June Color: Purple or deep blue Bird: Crow

Hawthorn blooms at Beltane and marks the threshold between spring and summer, between the safe and the wild, between the known and the enchanted. In Irish folk tradition, lone hawthorn trees were considered fairy trees, portals to the Otherworld. To cut one was to invite serious consequences.

Huath in a reading urges patience and caution. You are at a threshold, and thresholds demand respect. Do not rush through. Do not force the crossing. Stand at the boundary, observe what lies on the other side, and wait until the way is truly open before you step through.

In spiritual practice: Huath is the guardian of thresholds. Its medicine is the wisdom of pause, the recognition that the liminal space between one phase and the next carries its own teaching that will be lost if you hurry past it.

Duir -- Oak

Letter: D Tree: Oak (Quercus) Season: Mid-June to mid-July Color: Black or dark brown Bird: Wren

Oak is the king of the forest and the tree most closely associated with the druids. The word "Duir" also means "door," linking oak to doorways and thresholds of a different kind than hawthorn's: the doorways that open when you stand in your full strength and authority.

Duir in a reading calls for strength, endurance, and leadership. It is time to stand firm, to take responsibility, to step into your authority without apology. Duir does not bluster or dominate. True oak strength is quiet, rooted, and immovable. It does not need to prove itself.

In spiritual practice: Duir is the energy of sovereignty, of standing at the center of your own life with the calm confidence of a tree that has weathered centuries.

Tinne -- Holly

Letter: T Tree: Holly (Ilex aquifolium) Season: Mid-July to mid-August Color: Dark grey Bird: Starling

Holly is the evergreen warrior, armed with sharp, spiny leaves that protect it from browsers even in the depths of winter. In the mythic cycle of the Oak King and Holly King, holly rules the dark half of the year, maintaining its vitality and beauty when the deciduous trees have surrendered their leaves.

Tinne in a reading brings the energy of the spiritual warrior: the one who maintains their fire even in dark and challenging times. It speaks of challenges that test your resolve and of the fierce grace required to meet them without losing your center.

In spiritual practice: Tinne calls you to examine what you are fighting for and whether your fighting spirit is directed by wisdom or by reactivity. The holly warrior fights with purpose, not with anger.

Coll -- Hazel

Letter: C Tree: Hazel (Corylus avellana) Season: Mid-August to mid-September Color: Brown Bird: Crane

Hazel is the tree of wisdom and poetic inspiration. The Salmon of Knowledge, the most famous wisdom-being in Irish mythology, gained its power by eating hazelnuts that fell into the Well of Wisdom from the nine sacred hazel trees that surrounded it.

Coll in a reading brings the energy of creative insight, sudden understanding, and the flash of inspired knowledge that arrives whole and unbidden. It is not the slow accumulation of facts but the lightning strike of comprehension that changes everything.

In spiritual practice: Coll is the energy of the poet, the seer, the one who dips into the well of inspiration and returns with something that transforms the listener. When Coll appears, your creative and intellectual capacities are heightened. Trust what comes through.

Quert -- Apple

Letter: Q Tree: Apple (Malus) Season: Mid-September (associated with autumn equinox) Color: Green Bird: Hen

Apple is the tree of beauty, love, choice, and the Otherworld. The mythic island of Avalon, Emain Ablach in Irish, the "Island of Apples," is the blessed realm where the weary go for healing and the wise go for revelation. The apple has been a symbol of love, temptation, and paradise across many cultures.

Quert in a reading brings the energy of beauty, of choosing what nourishes the soul, and of access to the enchanted realms of life. It asks you to choose beauty, to choose love, and to trust that the Otherworld is not a distant fantasy but a dimension of experience available to you right now through attention, creativity, and openness.

In spiritual practice: Quert is the energy of enchantment in its highest sense: the recognition that the world is more beautiful, more alive, and more deeply meaningful than your ordinary perception allows you to see.

Third Aicme: The Transformation

Muin -- Vine or Bramble

Letter: M Tree: Vine (Vitis) or Bramble (Rubus) Season: Late September to late October Color: Variegated Bird: Titmouse

Vine produces the grape, which becomes wine, the ancient agent of loosened consciousness and prophetic vision. Muin represents the harvest, the gathering of what has ripened, and the willingness to release ordinary rational control in order to access deeper knowing.

Muin in a reading says the harvest is ready. Gather what you have grown. It may also indicate that you need to loosen your grip on rationality and allow a more intuitive, visionary mode of consciousness to emerge.

In spiritual practice: Muin is the energy of the prophet and the harvest-gatherer combined. It asks what you have grown this season and whether you are willing to taste the fruit.

Gort -- Ivy

Letter: G Tree: Ivy (Hedera helix) Season: Late October to late November Color: Sky blue Bird: Swan

Ivy is the relentless seeker, the spiral path that winds its way upward no matter how dark the forest. Ivy grows where other plants fail, clinging and persisting, finding its way by touch in conditions where sight is useless.

Gort in a reading speaks to the search that does not give up. The path is winding and the destination is not visible, but the direction is correct. Keep going. The spiral will bring you where you need to be, even though the route seems circuitous.

In spiritual practice: Gort represents the mature spiritual seeker who has given up the fantasy of a straight line to enlightenment and accepted the reality of the spiral path.

nGetal -- Broom or Reed

Letter: nG Tree: Broom (Cytisus scoparius) or Reed (Phragmites) Season: Late November to late December Color: Grass green Bird: Goose

Reed is hollow, a natural channel between worlds. It was used to make pens and arrows, connecting it to both communication and directed will. The Reed Moon encompasses Samhain, when the veil between worlds is thinnest.

nGetal in a reading asks you to become a channel, to let wisdom flow through you from deeper sources. It may also indicate the need for direct, targeted action, the arrow released from the bow with clear intent.

In spiritual practice: nGetal is the energy of the hollow bone, the shamanic principle of becoming an empty vessel through which spirit can speak and act.

Straif -- Blackthorn

Letter: St (Z) Tree: Blackthorn (Prunus spinosa) Season: Associated with dark moon Color: Purple Bird: Thrush

Blackthorn is fierce and dark. Its thorns are long, sharp, and notorious for causing wounds that are slow to heal. It blooms in early spring, white flowers appearing on black, leafless branches, an image of beauty emerging from severity. Blackthorn's fruit, the sloe berry, is too bitter to eat raw but becomes the base for sloe gin after the first frost transforms it.

Straif in a reading brings challenging energy. It indicates a period of difficulty, testing, or necessary confrontation with something dark. Blackthorn does not offer comfort. It offers the hard truth that some transformation requires pain, and that the beauty and sweetness that eventually emerge are inseparable from the severity that preceded them.

In spiritual practice: Straif is the energy of the dark night of the soul, the passage through thorns that cannot be avoided, only endured. Its promise is that what lies beyond the thorns is worth the wounds.

Ruis -- Elder

Letter: R Tree: Elder (Sambucus nigra) Season: Winter solstice period Color: Red Bird: Rook

Elder is the tree of endings, the final letter of the third aicme and the guardian of the threshold between death and rebirth. In Celtic folk tradition, elder was associated with the Cailleach, the crone of winter, and with the fairy folk. Elder wood was never burned in the hearth, and cutting an elder tree without permission was considered extremely unlucky.

Ruis in a reading signals an ending. Something is completing its cycle. This may be painful, but Ruis reminds you that in Celtic cosmology, death is never final. It is the necessary precursor to rebirth. The elder tree's ability to regenerate from even the most severe cutting reflects this truth.

In spiritual practice: Ruis is the energy of the wise elder, the one who has seen enough cycles to know that every ending contains the seed of a new beginning.

Fourth Aicme: The Completion

Ailm -- Pine or Silver Fir

Letter: A Tree: Pine (Pinus) or Silver Fir (Abies alba) Season: Winter solstice Color: Piebald Bird: Lapwing

Pine is evergreen, tall, and straight. It carries the scent of resin that has been used for purification and healing across many cultures. Pine represents clarity of vision, the long view that comes from height, and the perspective gained by standing apart from the crowded forest floor.

Ailm in a reading brings the gift of perspective and foresight. It asks you to look ahead, to take the long view, and to orient yourself by what endures rather than what is merely immediate.

In spiritual practice: Ailm is the energy of clear sight and elevated perspective, the ability to see past present difficulties to the larger arc of your journey.

Onn -- Gorse or Furze

Letter: O Tree: Gorse (Ulex) Season: Spring equinox Color: Gold Bird: Cormorant

Gorse blooms with vivid golden flowers even in the poorest soil and the harshest conditions. Its brightness against barren hillsides is an act of defiance against scarcity. Gorse represents the ability to find abundance and beauty even when external conditions seem to offer nothing.

Onn in a reading reminds you that your capacity for joy and vitality does not depend on ideal circumstances. Even in difficulty, there is gold to be found if you look with the right eyes.

In spiritual practice: Onn is the energy of hope that is rooted not in denial but in the genuine recognition that life persists and blooms in even the hardest ground.

Ur -- Heather

Letter: U Tree: Heather (Calluna vulgaris) Season: Summer solstice Color: Resinous Bird: Lark

Heather blankets the high moorlands in purple, transforming austere and windswept landscapes into fields of color. It is the plant of passion, of generosity, and of the inner fire that warms from within.

Ur in a reading brings the energy of passion, healing, and generosity of spirit. It may indicate a time when you are called to give freely, to heal others, or to allow your own inner fire to burn more brightly.

In spiritual practice: Ur is the energy of the healer and the lover, the one whose warmth transforms barren landscapes into places of beauty.

Eadha -- Aspen or White Poplar

Letter: E Tree: Aspen (Populus tremula) Season: Autumn equinox Color: Silver-white Bird: Swan

Aspen's leaves tremble at the slightest breeze, creating a distinctive whispering sound that is unlike any other tree. This trembling gave aspen its folk name, "the whispering tree," and associations with communication with the spirit world, with the voices of the dead, and with the ability to hear what cannot be heard through ordinary listening.

Eadha in a reading invites you to listen beyond the surface. There are communications coming through subtle channels, through whispers, synchronicities, and the quiet voices that speak only when the louder noises have subsided.

In spiritual practice: Eadha is the energy of subtle perception, of the spiritual ear that hears what the physical ear misses.

Ioho -- Yew

Letter: I (J) Tree: Yew (Taxus baccata) Season: Associated with the cycle's renewal point Color: Dark green Bird: Eagle

Yew closes the Ogham cycle with the ultimate tree of death and rebirth. Yew can live for thousands of years. It regenerates by sending new roots down through its own hollowed trunk. It is evergreen and toxic, a living paradox of death and eternal life.

Ioho in a reading speaks to transformation of the deepest kind. Something is ending and being reborn simultaneously. The old form is hollowing out, and from within that hollow, new life is already growing. Ioho does not ask whether you are ready. The transformation is already happening.

In spiritual practice: Ioho is the energy of the immortal self, the part of you that persists through every death and rebirth, the ancient wisdom that lives in your bones.

Beginning Your Ogham Practice

Start by learning the twenty trees. Not from this guide alone, but from the trees themselves. Find as many of the Ogham trees as you can in your local landscape. Spend time with each one. Learn to identify them by bark, leaf, flower, and fruit. The Ogham is a language of living beings, and you cannot learn a language without spending time with its native speakers.

Carve or paint the Ogham letters on twenty staves of wood, ideally using wood from the corresponding tree for each letter. Draw one stave daily, as you would draw a rune, and sit with its teaching. Over time, the twenty trees will become twenty teachers, each with a distinct voice and a wisdom that deepens with every encounter.

The Ogham is patient. The trees have been holding this wisdom for centuries. They will hold it for you as long as you need.