early 15c., "stab with a sword, kill," also "remove the ovaries of (a hunting dog)," from Anglo-French espeier "cut with a sword," from Middle French espeer, from Old French espee "sword" (French épée), from Latin spatha "broad, flat weapon or tool," from Greek spathe "broad blade" (see spade (n.1)). Compare Greek spadon "eunuch." Related: Spayed; spaying.