dripper

/ˈdrɪpər/
noun
  1. A device or part of a device that causes liquid to fall in drops, especially a coffee maker component or a watering system part.
    • The chemist used a glass dripper to add the solution drop by drop.
    • The dripper on the coffee machine got clogged with mineral deposits.
    • He installed a dripper in the garden to water the plants slowly.
Synonyms