tamp

 
Pronunciation: /tamp/

verb

[with object]
  • pack (a blast hole) full of clay or sand to concentrate the force of the explosion: when the hole was tamped to the top, gunpowder was inserted
  • [with object and adverbial of direction] ram or pack (a substance) down or into something firmly: he tamped down the tobacco with his thumb

Origin:

early 19th century: probably a back-formation from tampin (interpreted as 'tamping'), variant of tampion