What does "leak" mean?

Leak: The entrance or escape of a fluid through a crack, fissure, or other aperture; as, the leak gained on the ship's pumps. To spring a leak, to open or crack so as to let in water; to begin to let in water; as, the ship sprung a leak.

Additional senses

  1. 2.Leaky. [Obs.] Spenser.
  2. 3.To let water or other fluid in or out through a hole, crevice, etc.; as, the cask leaks; the roof leaks; the boat leaks.
  3. 4.To enter or escape, as a fluid, through a hole, crevice, etc. ; to pass gradually into, or out of, something; -- usually with in or out. To leak out, to be divulged gradually or clandestinely; to become public; as, the facts leaked out.

Sources