caboose

noun6

1. •
   (US) The last car on a freight train, consisting of cooking and sleeping facilities for the crew; a guard’s van.
2. •
   (slang, euphemistic) The buttocks.

   • That's a pretty big caboose for a baby. — 2001
3. •
   [in compounds] (informal) A youngest child who is born after a long gap in time.

   • Jimmy was seven and had just finished first grade, so that made Nancy our caboose baby — our bonus child — our swan song. — 1987
4. •
   (slang) The person or team in last place.
5. •
   (historical) A small sand-filled container used as an oven on board ship.

   • A tremendous billow, fringed with foam, swept over our deck, carrying the cook's caboose, cooking utensils and stove right overboard into the sea. — 1881
6. •
   (no longer used) A small galley or cookhouse on the deck of a small vessel.