What does the word stick mean?

Usage examples for stick

  1. But you must take heart and stick by yourself, or we shall never pull you through." – Tom Brown at Oxford by Thomas Hughes
  2. An' I'm tellin' you why: Did you ever hear a man tell of a stick- up party on a night like this? – Six Feet Four by Jackson Gregory
  3. Why the deuce didn't he stick to it? – The Testing of Diana Mallory by Mrs. Humphry Ward