'backsaw' originates from English, specifically a compound of the words 'back' and 'saw', where 'back' referred to the stiffened rear edge (the rib) and 'saw' referred to the cutting tool.

'back' comes from Old English 'bæc' (meaning the rear) and 'saw' from Old English 'sagu'; the compound appears in Modern English as 'back-saw' and later as the solid form 'backsaw'.

Initially it simply denoted 'a saw with a back (stiffening rib)'; over time the term came to specifically refer to the class of small, fine-toothed saws used for precise joinery.