Aicme Muine

Aicme Muine is the third group, named for muin, and its five letters are muin, gort, ngetal, straif and ruis, giving the sounds m, g, ng, z or st, and r. In the script these are cut as one to five strokes crossing the stemline diagonally. Two of the five, ngetal and straif, represent sounds whose value is uncertain and which are rare or absent in the inscriptions, and the letter names themselves are in several cases obscure; the meanings given to them in the medieval Irish tradition are partly guesses by later scholars working on a script that had already gone out of use. This is worth stating because a great deal of modern writing treats the ogham letter meanings as a settled body of tree lore, and they are not.

The name muin is at least as unsettled as uath: Old Irish has three unrelated words spelled muin, neck or upper back, related to Welsh mwn and Latin monile, a neck ornament; wile or ruse; and love or esteem, and which of the three, if any, actually named the letter is not known with confidence. The Auraicept's arboreal tradition instead glosses the letter as vine, a reading modern scholarship treats with particular suspicion, since the ordinary Old Irish word for a grapevine was finemain, a loan from Latin, and grapevines are not native to Ireland, making the vine gloss look like a later, retrospective tree assignment rather than a genuine original meaning.

Sources A Guide to OgamDamian McManus with Auraicept na n-Eces: The Scholars' PrimerGeorge Calder (ed.)

The four ogham families are told apart by the angle at which their strokes meet the writing line, not by where they sit along it.

The geometry

Aicme Muine is cut as strokes crossing the line at an angle. Its five members carry one to five oblique strokes: Muin, Gort, nGetal, Straif and Ruis, with the values M, G, NG, a sibilant written Z in the manuscripts, and R.

Because these strokes cross the line rather than sitting beside it, they cannot be confused with the first two families however the reader is standing. That is the practical advantage of changing the geometry rather than simply moving the strokes further along.

The hardest family to cut and to read

On a standing stone every one of these strokes has to be carried across the arris and down both faces at a consistent angle. Execution varies more in this family than in the first two, and a five-stroke oblique character such as Ruis is the single most difficult letter in the system to read on a weathered stone. A lost stroke turns one valid letter into another valid letter, since there is no redundancy anywhere in ogham.

Two letters with unsettled values

nGetal and Straif are both rare in the surviving inscriptions and both have values that the manuscripts supply rather than the corpus confirming. The manuscript values are recorded here as manuscript values, and the earlier ones are treated as open.