noun
Etymology: slip (III)
1.
a. : a telescopic joint between two parts (as a piece of tubing and packing material in a stuffing box) that permits the parts to move in a lengthwise direction
b. : a joint formed by slipping one part over another of nearly the same size and uniting the two (as by brazing)
2. : a channel or groove cut in an existing wall to receive the ends of the brick of a new wall