Gahan (surname) Irish language "Mac Gaoithín", meaning "son of "Gaoithín"", although the more common Anglicised form of this Gaelic name is "McGeehan" in Ulster. Gahan (surname) Gahan (and its variant Gahame) is a surname with several different origins. One origin of the surname is from a reduced form of "McGahan", which is in turn an Anglicised form of the Irish language "Mac Eacháin", meaning "son of "Eachán"". Another origin of the name, in Leinster, is from a reduced form of the Irish language "Ó Gaoithin", meaning "descendant of "Gaoithín"". The personal name "Gaoithín" is a diminutive of "gaoth", meaning "wise", or "wind".
Irish people used. While both "Mac" and "Ó'" prefixes are Gaelic in origin, "Mac" is more common in Scotland and in Ulster than in the rest of Ireland; furthermore, "Ó" is far less common in Scotland than it is in Ireland. The proper surname for a woman in Irish uses the feminine prefix nic (meaning daughter) in place of mac. Thus a boy may be called Mac Domhnaill whereas his sister would be called Nic Dhomhnaill or Ní Dhomhnaill – the insertion of 'h' follows the female prefix in the case of most consonants (bar H, L, N, R, & T). A