The Collaborative International Dictionary
Center punch \Center punch\, or Centre punch \Centre punch\ (Mech.)
A punch for making indentations or dots in a piece of work, as for suspension between lathe centers, etc.
A punch for punching holes in sheet metal, having a small conical center to insure correct locating.
Wiktionary
n. 1 (context countable English) a device used to create a small indentation in preparation for drilling a hole 2 (context countable English) the small indentation created by such a device vb. to create a small hole or indentation in a workpiece as a guide in preparation for drilling
WordNet
v. make a small hole in something as a guide for a drill
Usage examples of "center punch".
There were three small holes in the stoneshallow depressions that might have been formed by a lightly tapped center punch.
Early Wednesday morning, Macon dreamed Grandfather Leary woke him and asked where the center punch was.