Old Irish Ogam (pronounced [ˈoɣəm]), in Modern Irish spelling Ogham [ˈoːm], is the name of a writing system, not of a language.2 The language that is prototypically written in Ogam script is the earliest known stage of the Irish language, called Primitive Irish. The origin of the name Ogam is disputed (cf. Thurneysen 1937). It displays a blatant simi-larity with Ogma, the name of an Early Irish mythological, semi-divine figure, whose name in turn evokes that of the Gaulish mythological figure Ogmios (Ὄγμιος), mentioned by the 2nd-century Greek author Lucian of Samosata as a psychopompos (Hofeneder 2006) and attested as an underworldly figure on lead-tablets from Bregenz (Austria). The connections, if there are any, among the mythological figures and the writing system are unclear. In an Isidorian-style etymology it has been suggested to analyse the word Ogam as a compound og-úaimm ‘pricker-pricking’ (McManus 1991: 152‒153, Sims-Williams 2018: 119), despite serious formal difficulties with this explanation (it has the wrong inflectional class; syncope, i.e. loss of the middle vowel, should not occur in the derivative ogmóir ‘one who is skilled in writing Ogam’). This etymology would also remove the basis for a connection with the names Ogma and Ogmios.