miter box
noun
: a device for guiding a handsaw at the proper angle in making a miter joint in wood
Example Sentences
Recent Examples on the Web Amber used a clamping miter box ($15, The Home Depot) to hold the dowel and ensure even cuts. 
Amber Kemp-gerstel, Better Homes & Gardens, 9 Dec. 2021 Cut four 3/4-inch square wood dowels to the tile height using a miter box and saw. Beth Eslinger, Better Homes & Gardens, 15 July 2021
Amber Kemp-gerstel, Better Homes & Gardens, 9 Dec. 2021 Cut four 3/4-inch square wood dowels to the tile height using a miter box and saw. Beth Eslinger, Better Homes & Gardens, 15 July 2021 Word History
First Known Use
1678, in the meaning defined above