from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An instrument with straight edges that are set at a 45° angle or that are adjustable, used for marking the angles of a miter joint.
from the GNU version of the Collaborative International Dictionary of English
- n. a bevel with an immovable arm at an angle of 45°, for striking lines on stuff to be mitered; also, a square with an arm adjustable to any angle.
Sorry, no etymologies found.