noun, Philately. 1. a group of stamps that differ in color, value, or design but are printed together on the same sheet and are collected without separating the stamps.
A markup scheme intended for documents that are both human- and computer-readable.
- Set foot
1. set foot in. Enter, as in I’ll never set foot in this house again. 2. set foot on. Step on, as in We were so happy to set foot on dry land. [ c. 1600 ]
noun, Mathematics. 1. a function having a collection of sets as domain.