The Collaborative International Dictionary of English v.0.48:

Interment \In*ter"ment\, n. [OE. enterment, F. enterrement. See
   Inter, v. t.]
   The act or ceremony of depositing a dead body in the earth;
   burial; sepulture; inhumation. --T. Warton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

interment
    n 1: the ritual placing of a corpse in a grave [syn: burial,
         entombment, inhumation, interment, sepulture]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "interment":
   burial, burying, clouding, concealedness, concealment, covering,
   covering up, covertness, darkening, deception, entombment,
   hiddenness, hiding, inhumation, invisibility, masking,
   mystification, obscuration, obscurement, occultation, putting away,
   screening, secrecy, secretion, sepulture, subterfuge,
   uncommunicativeness