Terms of the Trade: What Is a T-Square?

A wooden t-square next to a rolled up piece of paper.

This tool is largely used by draftsmen to draw and measure out horizontal lines on a drafting table. However, it's also used by many DIYers to measure and cut drywall. You'll find that some table saws have T-squares, as well. The longer portion of the tool is known as the "blade" while the shorter end is known as the "stock" or "head."