Other forms: tamping; tamped; tamps
To tamp is to push or pack down a loose or granular material. If you work as a barista, you'll learn to tamp espresso grounds before running hot water through them.
Before a road is paved or a patio is laid out, workers will tamp gravel to provide a sturdy, level base. Old-fashioned, muzzle-loading guns had to be filled with gunpowder, which the user would need to tamp firmly before firing. The tool used to do the tamping is sometimes also called a tamp.