Ogham Dictionary

Ogham is the tree alphabet of the Celtic world: twenty letters, each named after a tree, carved as straight lines along the edges of stone. This dictionary gives every letter, its tree, and the traditional meaning the tree carries.

BeithBirchbeginnings and renewal: the first letter, the tree that grows back after fire, cleansing and fresh starts

LuisRowanprotection and quickening: the shield tree, worn against harm, and the sudden flash of insight

FearnAlderresilience and the threshold: the tree that stands in water, courage under pressure, the bridge between worlds

SailleWillowintuition and flow: the moon tree, cycles, dreams, and the bend that does not break

NionAshconnection and the axis: the world tree, the link between the worlds, balance and rootedness

UathHawthornthe threshold and the guardian: protection, the boundary, and the door that must be respected

DairOakstrength and endurance: the king tree, stability, the long view, and the door of the stronghold

TinneHollythe spear and the crown: clarity under attack, determination, and the warrior's honor

CollHazelwisdom and inspiration: the poet's tree, the well of knowledge, creative insight

MuinVineconnection and intoxication: the spiral, prophecy, and the ties that bind and teach

GortIvythe spiral path: growth through difficulty, fidelity, and the green that survives the winter

NgetalReedthe hidden spear: concealment, the music of the wind, and the strike that comes from stillness

StraifBlackthornthe dark door: difficulty, the wren's warning, and the transformation that follows hardship

RuisElderendings and the cauldron: the gate of the otherworld, completion, and the renewal that comes after

AilmFir / Elmclarity and the long sight: the tallest tree, vision from the heights, and the beginning of wisdom

OnnFurze / Gorsethe hearth and the light: warmth, gold, and the fire that burns through the dark

UrHeatherthe earth and the queen: grounding, the sacred landscape, and luck of the land

EadhadhAspenthe trembling tree: sensitivity, the whisper of spirits, and the quivering boundary

IodhadhYewthe eternal: death and rebirth, the long memory, and the tree that outlives all others

EabhadhAspen / Yew pairthe final union: the meeting of all opposites, the completion of the alphabet, and the song of creation

Updated August 23, 2026: the twenty letters of the classical Ogham with the tree lore of the tradition.

What Ogham Is

Ogham is the earliest written form of the Irish language, and the only alphabet native to the British Isles. It survives on several hundred standing stones, mostly in Ireland, Scotland, and Wales, dating from roughly the fourth to the seventh century. The alphabet is built from straight lines: a central stem line, with one to five strokes crossing it, above it, or below it. It was designed for stone: the letters are easy to carve and almost impossible to mistake, which is why the stones have survived fifteen hundred years of weather.

The tradition attached a tree to every letter. Some of the names are certain (Beith is birch, Dair is oak, Coll is hazel), and the tree lore grew around them into a complete symbolic system. The Ogham tree calendar, in which each letter rules a period of the year, is a later reconstruction, but the letter meanings are old: the trees carried their qualities long before the alphabet, and the alphabet borrowed them.

The Four Groups of Five

The twenty letters are arranged in four groups of five, the aicme. The first group (Beith, Luis, Fearn, Saille, Nion) runs from birch to ash: the letters of beginning and connection. The second (Uath, Dair, Tinne, Coll, Muin) runs from hawthorn to vine: the letters of protection, strength, and the poet's wisdom. The third (Gort, Ngetal, Straif, Ruis, Ailm) runs from ivy to fir: the letters of the hard path and the long sight. The fourth (Onn, Ur, Eadhadh, Iodhadh, Eabhadh) runs from furze to the final pair: the letters of the hearth, the earth, and the completion of the cycle. Reading a draw from a single group gives the reading its tone: beginnings, protection, transformation, or completion.

How to Use the Letters

The simplest use is the single-letter draw, exactly like a rune: frame a question, draw one letter, and read the tree's meaning as the answer. Beith answers with a beginning, Dair with a call for endurance, Ruis with an ending. The three-letter draw refines this: the first letter is the situation, the second the action, the third the outcome. The dictionary readings above are the vocabulary for both methods: the tree, its core quality, and the practical meaning.

Ogham is also used for inscription: your name carved in Ogham strokes on a stone, a wand, or a piece of jewelry. The letters are written left to right along a stem, one to five strokes per letter, and the result is one of the most distinctive scripts in the world, still used today for exactly that purpose. The letters of a name carry the meanings of their trees, which is why the dictionary is useful for choosing the reading of an inscribed name as well as for divination.

Frequently Asked Questions

What is the Ogham alphabet?

Ogham is the earliest written form of the Irish language: an alphabet of twenty letters, each named after a tree, inscribed as straight lines along the edge of stone. It dates from roughly the fourth century and survives on hundreds of standing stones across Ireland, Scotland, and Wales.

How many letters are in Ogham?

The classical Ogham has twenty letters in four groups of five (the aicme), named after trees: Beith (birch), Luis (rowan), Fearn (alder), and so on. Five additional letters were added later for sounds not in the original alphabet.

What does each Ogham letter mean?

Each letter is named after a tree and carries the tree's traditional meaning: Beith (birch) is beginnings and renewal, Dair (oak) is strength and endurance, Coll (hazel) is wisdom and inspiration, Iodhadh (yew) is death and rebirth. The tree lore of the tradition gives each letter a full set of associations.

How do I use Ogham for divination?

The twenty letters are drawn the way runes are: one letter per question, read by the tree's meaning. The draw is usually answered by the letter's core quality (Beith: a beginning, Dair: endurance is needed, Ruis: an ending is near), and the surrounding letters refine the reading.

Is Ogham connected to the runes?

They are parallel systems, not relatives: the runes come from the Germanic world, Ogham from the Celtic world. Both are alphabets used for writing, both became divinatory systems, and both are tied to a body of tree or symbol lore, but their origins are independent.

Sources

The letter names and trees follow the classical Ogham tradition as transmitted in the medieval Irish manuscript tradition (the Book of Ballymote and the Auraicept na n-Éces). The tree meanings follow the consensus of the Celtic tree lore, consistent with the tree symbolism used in the rune and symbol dictionaries on this site.