Ogam n. : Same as Ogham.

Example:
Ogam trees?

Taxonomy
ogham, Old Irish, BCE, alphabet, scholars, inscriptions, Ogam, tree, Beith, theories, McManus, Ogham Stone, Ogham Inscriptions, Primitive Irish, language, Macalister, ogham alphabet, OCLC.

Defination from the web:
ogam or ogham remains unclear. ... Alternatively, the Ogam Tract credits Ogma mac Elathan (Ogmios) with the script's invention. ... Thurneysen, Zum ogam Beiträge zur Geschichte der deutschen Sprache und Literatur, pp196–7, 1937 ...