Etymology
Various origins:
* In general, from Old English ġemǣne (“common, shared”) + tūn (“enclosure; settlement”).
* In the case of the village in Lincolnshire, from Old English mealm (“sand, chalk”) + tūn (“enclosure; settlement”).
* The surname can also be an Anglicized form of Irish Ó Manntáin (“descendant of Manntán”), a nickname derived from a diminutive of mantach (“toothless”).