Mullinax
A surname of uncertain origin, probably a later spelling or anglicized form of a name in the Mullin/Mullen family group.
The #7,148 most common surname in the United States (2010 Census) — about 1 in every 65,985 Americans shares it.
Etymology
The surname Mullinax is not securely explained in the historical material available here. It likely belongs to the wider family of names built on Mullin, Mullen, or similar forms, which in turn may reflect Irish Gaelic surnames or place-based forms that were later altered in English spelling. The final -ax spelling looks like an American or regional variant that developed from pronunciation and record-keeping rather than from a distinct original word.
History
The excerpted source only shows early-modern London records with spellings like Mullinax and Mollinox, which suggests the name was already being written in more than one way by the 1600s. In the United States, Mullinax is best known as a relatively uncommon surname, especially in the South and Appalachia, where many surnames of British and Irish origin took on stable local spellings.
Origin
Regions
Variant spellings
Fun fact
Early parish-register spellings show that Mullinax and Mollinox were once close enough in sound to be used for the same family line.
From the historical record
“ibid. 1603. Buried — James Mullinax: St. Michael, Comhill, p. aia. 1634. Bapt. — Henry, s. John Mollinox : St. Jas. Clerkenwell, 1. ia6.”
— A Dictionary of English and Welsh Surnames (alternate scan)