compartment

noun

1. A room, or section, or chamber, typically within a vehicle.

   “Two men were seated in a well-lit compartment of a third-class railway carriage.”

   “This is a second-class ticket. And you're sitting in the first class!” “I'd no idea,” Haldiram said. “I didn't know what compartment was this.” And looking around, he asked, “Where does it say First Class? I still can't see it.”

   “Because of the heavy traffic, the 1960-61 Christmas guide to trains between King's Cross and the north stated: "To make travel conditions as comfortable as possible, passengers are requested to raise arm rests to enable four people to be seated on each side of those compartments which are fitted with arm rests."”

2. One of the parts into which an area is subdivided.
3. The part of a protein that serves a specific function.
4. A mound (often of grass), shelf (of e.g. wall) or other thing beneath the shield in a coat of arms on which the supporters stand.
5. A region in the body, delimited by a biological membrane.

verb

1. (transitive)To arrange in separate compartments.