noun
or og·am also og·um ˈägəm, ˈȯg-
( -s )
Etymology: Irish Gaelic & Middle Irish; Irish Gaelic ogham, from Middle Irish ogom, ogum
1. sometimes capitalized : a system of alphabetic writing which is known principally from inscriptions in Old Irish running vertically up rough standing memorial stones that date from at least as early as the 5th century and are found in the British Isles especially in southern Ireland and which in its typical form had 15 consonant symbols consisting of lines touching or crossing an edge of the stone and five vowel symbols consisting of notches on the edge
2. : a letter of the ogham alphabet
3. : an inscription in ogham characters
4. : the form of Old Irish appearing in ogham inscriptions