The surname originated as a patronym, however it no longer refers to the actual name of the bearer's grandfather.

There are specific forms of these surnames that are borne by married and unmarried females.

[3] These surnames originated as patronyms, however they no longer refer to the actual name of the bearer's grandfather.

The surnames Ó Tomhrair and Ó Tomhnair have historically been anglicised variously as Toner;[2] Woulfe, who wrote in the early 20th century, noted that the surname was then common in Ulster.

This family built a church called Cill Ó dTomhrair, which is now Anglicised as Killodonnell.