Iain Lom's family were of the MacDonalds of Keppoch. In Gaelic society, since there might often be a number of men with the same first names in any given clan, they were given sobriquets which might be based on a peculiar characteristic or feature. "Lom" is Scots Gaelic for "bald" or "bare" (lom a., comparative form luime, bare, bald, shaven, cropped), perhaps indicating he was bald. However, in Gaelic idiom, it can also mean one who is very plain-spoken, an idiom which perhaps can best be related in English to the term "bare-faced" (though this is now generally applied only to liars). He was also known as Iain Manntach which translates as "stammering John," perhaps from a speech impediment.