bow saw

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

• noun A saw with a slender blade connected at each end to a narrow handle that curves outward like an archer's bow.

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

• noun A lightweight metal-framed saw in the shape of a bow with a removable coarse wide blade, used for cutting tree trunks.
• noun A woodworking saw used for straight or curved cuts.