The Collaborative International Dictionary of English v.0.48:
Backsaw \Back"saw`\ (b[a^]k"s[add]`), n. [2d back, n. + saw.] A saw (as a tenon saw) whose blade is stiffened by an added metallic back. [1913 Webster]WordNet (r) 3.0 (2006):
backsaw n 1: a handsaw that is stiffened by metal reinforcement along the upper edge [syn: backsaw, back saw]