Onn
The second vowel of ogham, two notches or strokes across the stem line, for the sound o. The medieval Auraicept calls it furze; Damian McManus reads the name as the ash tree.
Meaning
Onn is two notches on the edge, or two short strokes across the line. Here the medieval reading and the modern one part ways in an unexpected direction: the Auraicept na nÉces calls it “furze”, gorse, but Damian McManus, as the Ogham in 3D project at the Dublin Institute for Advanced Studies gives his list, reads it as “ash-tree”, and Deborah Hayden and David Stifter of the OG(H)AM project count onn among the names that really are trees. They add that the commoner Old Irish word for the ash is uinnius, made from it. Unicode encodes the letter as U+1691 OGHAM LETTER ONN.
Origin and history
In Lebor Ogaim hedges, offering “furze or ash”. Its Word Ogham kennings are “helper of horses”, explained by the wheels of a chariot, and “smoothest of work”. The Heritage Council’s guide reports McManus’s conclusion that only six of the twenty letter names were trees in the first place; onn, the ash, is one of them.
Two notches or three?
Counting notches on a worn edge is hard. On Greenhill I in County Cork the OG(H)AM project found only two notches at the end of the name TRENU, which would make the last letter O, but room for a third that would make it U, as Macalister read it in 1945.
On the stones
O is in MUCOI, “posterity, tribe”, and KOI, “here”, as Ogham in 3D records.
Write in ogham
stringmash.comOgham translatorWrite English in ogham, the early Irish alphabet of strokes cut along an edge, with the full ogham chart.Read next
- Next in OghamÚrThe third vowel of ogham, three notches or strokes across the stem line, for the sound u. The medieval Auraicept calls it heath; its name means earth or soil.
- The same shape in Chinese radicalsCǎo 艸The character for ‘grass’, and radical 140 of the 214 Kangxi radicals, under which the names of plants and flowers are filed.
See also
Beithe, Luis, Fern, Sail, Nin, Úath.
Sources
- Ogham in 3D: alphabet, Ogham in 3D (2013 edition), letter names after Damian McManus, A Guide to Ogam (1991) and Ériu 39 (1988), Dublin Institute for Advanced Studies, alphabet; Letter names, Aicme Ailme
- Auraicept na n-éces: the scholars' primer, George Calder (ed. and trans.), 1917: the Ogham tract from the Book of Ballymote and the Yellow Book of Lecan, with In Lebor Ogaim, John Grant, Edinburgh (Internet Archive), Auraicept, p. 93; In Lebor Ogaim, pp. 277, 281, 287
- Ogam and trees, Deborah Hayden and David Stifter, 20 December 2022, OG(H)AM project, University of Glasgow and Maynooth University, §1, Onn
- Ogham Stones in Ireland, Nora White, Our Ancient Landscapes: Ogham Stones in Ireland (2021), The Heritage Council, p. 10, Ogham alphabet and letter names
- Og(h)am of the Month, OG(H)AM project team (Nora White, Patricia O’Connor, David Stifter and others), 2021–2025, OG(H)AM project, University of Glasgow and Maynooth University, March 2024: Greenhill I
- Ogham in 3D: ogham, Ogham in 3D (2013 edition), Dublin Institute for Advanced Studies, ogham: Content
- Ogham (Unicode code chart U+1680–U+169F), The Unicode Standard, code chart for the Ogham block, Unicode Consortium, U+1691
The same shape elsewhere
Browse symbols formed from letters and numbers or lines.
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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