billhook

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An implement with a curved blade attached to a handle, used especially for clearing brush and for rough pruning.

from The Century Dictionary.

• noun A form of small hatchet curved inward at the point of the cutting edge, used for pruning trees, hedges, and the like, and by sappers and miners to cut pickets, rods, and withes for gabions, fascines, hurdles, saprollers, etc.

from the GNU version of the Collaborative International Dictionary of English.

• noun A thick, heavy knife with a hooked point, used in pruning hedges, etc. When it has a short handle, it is sometimes called a hand bill; when the handle is long, a hedge bill or scimiter.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An agricultural implement often with a curved or hooked end to the blade used for pruning or cutting thick, woody plants.
• noun weaponry A medieval polearm with a similar construct, fitted to a long handle, sometimes with an L-shaped tine or a spike protruding from the side or the end of the blade for tackling the opponent; a bill
• noun Written as bill-hook: a part of the knotting mechanism in a reaper-binder or baler (agricultural machinery).
• noun Written as bill hook: a spiked hook used in offices and shops for hanging bills or other small papers such as receipts.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a long-handled saw with a curved blade