noun

• (military) A hardened shelter, often partly buried or fully underground, designed to protect the inhabitants from falling bombs or other attacks.
  "The military built a bunker to help evacuate the citizens safely from the bombings."
• (nautical) A compartment for storing coal for the ship's boilers; or a tank for storing fuel oil for the ship's engines.
• (rail transport) The coal compartment on a tank engine; it can also refer to that on a tender engine.
  "Among tank engines, the 0-6-2 wheel arrangement was by far the most numerous, there being nearly 450 of this arrangement, which offers the advantage of good power and adhesive weight, coupled with adequate tank and bunker capacity, within a limited compass."
• (sports)
  "[Letter X, page 204] At length I came within sight of them, three in number, where they sat cosily niched, into what you might call a bunker, a little sand-pit, dry and snug, and surrounded by its banks, and a screen of whins in full bloom. […] [Letter XI, page 223] And are ye in the wont of drawing up wi' all the gangrel bodies that ye meet on the high road, or find cowering in a sand-bunker upon the links?"

verb

• (nautical)
• (nautical)
• (nautical)
• (transitive, golf) To hit (a golf ball) into a bunker; (chiefly passive voice) to place (a golfer) in the position of having a golf ball in a bunker.

noun

• (British, slang) One who bunks off; a truant from school.

noun

• (US, regional) The menhaden, any of several species of fish in the genera Brevoortia and Ethmidium.
  "Ten hours of footage revealed the young [shark's] habits, such as diving for squid up to 150 feet deep, then moving closer to shore to feast on huge schools of bunker fish."