The Collaborative International Dictionary of English v.0.48:

Crypt \Crypt\ (kr[i^]pt), n. [L. crypta vault, crypt, Gr.
   kry`pth, fr. kry`ptein to hide. See Grot, Grotto.]
   1. A vault wholly or partly under ground; especially, a vault
      under a church, whether used for burial purposes or for a
      subterranean chapel or oratory.
      [1913 Webster]

            Priesthood works out its task age after age, . . .
            treasuring in convents and crypts the few fossils of
            antique learning.                     --Motley.
      [1913 Webster]

            My knees are bowed in crypt and shrine. --Tennyson.
      [1913 Webster]

   2. (Anat.) A simple gland, glandular cavity, or tube; a
      follicle; as, the crypts of Lieberk["u]hn, the simple
      tubular glands of the small intestines.
      [1913 Webster]

WordNet (r) 3.0 (2006):

crypt
    n 1: a cellar or vault or underground burial chamber (especially
         beneath a church)

Moby Thesaurus II by Grady Ward, 1.0:

114 Moby Thesaurus words for "crypt":
   Easter sepulcher, alveolation, alveolus, ambry, antrum, apse,
   armpit, baptistery, barrow, basement, basin, beehive tomb,
   blindstory, bone house, booth, bowl, box, box grave, burial,
   burial chamber, burial mound, catacomb, catacombs, cave, cavern,
   cavity, cell, cellar, cellule, cenotaph, chamber, chancel,
   charnel house, choir, cist, cist grave, cloisters, compartment,
   concave, concavity, confessional, confessionary, crater, crib,
   cromlech, cup, deep six, depression, diaconicon, diaconicum, dip,
   dokhma, dolmen, enclosed space, fold, follicle, funnel chest,
   grave, grotto, hold, hole, hollow, hollow shell, house of death,
   lacuna, last home, long home, low green tent, low house, manger,
   mastaba, mausoleum, monstrance, mummy chamber, narrow house, nave,
   ossuarium, ossuary, passage grave, pew, pit, pocket, porch,
   presbytery, punch bowl, pyramid, reliquary, resting place,
   rood loft, rood stair, rood tower, room, sacrarium, sacristy,
   scoop, sepulcher, shaft grave, shell, shrine, sink, sinus, socket,
   stall, stupa, tomb, tope, tower of silence, transept, triforium,
   trough, tumulus, vault, vestry, vug



The Free On-line Dictionary of Computing (30 December 2018):

crypt

   Unix command to perform encryption and decryption.