drainplug

/ˈdreɪnˌplʌɡ/
noun
  1. A plug or stopper used to close a drain hole, especially in a sink, bathtub, or engine, to prevent liquid from flowing out.
    • The mechanic removed the oil drainplug to change the engine oil.
    • He pulled the drainplug from the sink to let the water out.
    • Make sure the drainplug is securely in place before filling the bathtub.
Synonyms