twibill
(noun)
noun
1. An axe with two cutting blades
2. A mattock
3. A double bladed tool used in gate type hurdle making for cutting out mortices, with a flat chisel and a mortice chisel or hook, similar to the much larger french carpenter's tool, the bisaigue (or besaigue)
4. (obsolete) A double-bladed halberd or battle-axe