- an alphabetical script used originally for inscriptions in an archaic form of Irish, from about the 5th to the 10th centuries.
- any of the 20 characters of this script, each consisting of one or more strokes for consonants and of notches for vowels cut across or upon a central line on a stone or piece of wood.
- an inscription employing this script.
- an ancient alphabetical writing system used by the Celts in Britain and Ireland, consisting of straight lines drawn or carved perpendicular to or at an angle to another long straight line
n.also ogam, ancient Irish form of writing, 1620s, from Irish ogham, from Old Irish ogam, said to be from name of its inventor, Ogma Mac Eladan. But this appears to be from Celt. *Ogmios, perhaps from PIE *og-mo- “furrow, track,” thus metaphorically “incised line.” This could be the source of the name of the writing style, which looks like a series of cuts or incised lines, and the inventor’s name thus might be folk etymology. Related: Oghamic.