- English: variant of Fosse. There has been some confusion with northwestern English force in the sense of ‘waterfall’, it is possible that the surname may also have arisen as a topographic name for someone living by a waterfall.
- French: topographic name for someone who lived by a fortress or stronghold, Old French force, Late Latin fortia, a derivative of fortis ‘strong’ (see Fort). There are several places named with this word (for example in Aude, and baronial lands in the Dordogne), and it may also be a habitational name from any of these.
[Reference: Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4]