noun

• (obsolete) That which swallows; the gullet.
  "Witch's mummy, maw and gulf / Of the ravined salt sea shark,"
• (geography) A portion of an ocean or sea extending into the land; a partially landlocked sea
  "the Gulf of Mexico"
• (mining) A large deposit of ore in a lode.
• (figurative) A wide interval or gap; a separating space.
  "Between us and you there is a great gulf fixed."

verb

• (transitive) To engulf.
  "[…] if with thee the roaring wells ⁠Should gulf him fathom-deep in brine; ⁠And hands so often clasp’d in mine, Should toss with tangle and with shells."
• (Oxbridge slang, transitive) To award a degree to somebody who has only just passed sufficiently.
  "The mention of gulfed and plucked men brings me back to myself."