broach

Broach is a term with multiple meanings in English. It can denote a metalworking tool, a verb meaning to bring up a topic, or a historical practice of tapping a barrel to draw liquid. The precise sense is determined by context.

In metalworking, a broach is a long, hardened tool with a series of teeth that progressively remove material as it passes through or across a workpiece. It is used to bring a hole or external surface to a final shape or size with high precision. Internal broaches shape hollow profiles such as squares, hexagons, or splines; external broaches shape the outside of a workpiece. Broaching is typically performed on specialized machines and can produce smooth, accurate finishes, but often requires multiple passes or multiple broaches to reach the final geometry and tolerance.

As a verb, broach means to introduce a topic for discussion or to begin to discuss something, especially a sensitive issue. Example: “She broached the subject of pay changes at the meeting.”

In the context of barrels and casks, to broach means to tap or pierce the vessel and draw off its contents. This sense is common in discussions of traditional brewing or old wine trade.

Note: The terms "broach" and "brooch" are often confused; "broach" refers to the tool, action, or topic introduction, while "brooch" is a decorative pin.