Definition of "tomb"

tomb

/tuːm/

noun
plural tombs
1. A small building (or "vault") for the remains of the dead, with walls, a roof, and (if it is to be used for more than one corpse) a door. It may be partly or wholly in the ground (except for its entrance) in a cemetery, or it may be inside a church proper or in its crypt. Single tombs may be permanently sealed; those for families (or other groups) have doors for access whenever needed.
2. A pit in which the dead body of a human being is deposited; a grave.
  Quotations
  As one dead in the bottom of a tomb.
  c. 1591–1595 (date written), William Shakespeare, “The Tragedie of Romeo and Ivliet”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act III, scene v]
3. One who keeps secrets.
  Quotations
  I never told anyone about it. You're the first, except Ivan, of course—Ivan knows everything. He knew about it long before you. But Ivan's a tomb.
  1912, Fyodor Dostoyevsky, translated by Constance Garnett, The Brothers Karamazov, published 1880, Book III, chapter 4
verb
third-person singular simple present tombs, present participle tombing, simple past and past participle tombed
1. (transitive) To bury.