Source : Webster's Revised Unabridged Dictionary (1913)

Sarcophagus \Sar*coph"a*gus\, n.; pl. L. {Sarcophagi}, E.
   {Sarcophaguses}. [L., fr. Gr. sarkofa`gos, properly, eating
   flesh; sa`rx, sa`rkos, flesh + fagei^n to eat. Cf.
   {Sarcasm}.]
   1. A species of limestone used among the Greeks for making
      coffins, which was so called because it consumed within a
      few weeks the flesh of bodies deposited in it. It is
      otherwise called {lapis Assius}, or {Assian stone}, and is
      said to have been found at Assos, a city of Lycia.
      --Holland.

   2. A coffin or chest-shaped tomb of the kind of stone
      described above; hence, any stone coffin.

   3. A stone shaped like a sarcophagus and placed by a grave as
      a memorial.

Source : WordNet®

sarcophagus
     n : a stone coffin (usually bearing sculpture or inscriptions)
     [also: {sarcophagi} (pl)]

sarcophagi
     See {sarcophagus}