Watkins suggests it is perhaps from PIE root *teue- "to swell," but Beekes writes that it is probably a Pre-Greek (non-IE) word. He writes that Latin tumulus "earth-hill" and Armenian t'umb "landfill, earthen wall" "may contain the same Pre-Greek/Mediterranean word," and suggests further connections to Middle Irish tomm "small hill," Middle Welsh tom "dung, mound."
The final -b began to be silent about the time of the spelling shift (compare lamb, dumb). Modern French tombeau is from Vulgar Latin diminutive *tumbellus. The Tombs, slang for "New York City prison" is recorded from 1840.
"underground burial place," usually catacombs, from Old English catacumbas, from Late Latin catacumbae (plural) "sepulchral vaults," originally the region of underground tombs between the 2nd and 3rd milestones of the Appian Way (where the bodies of apostles Paul and Peter, among others, were said to have been laid) near Rome; the word is of obscure origin, perhaps once a proper name, or dissimilation from Latin cata tumbas "at the graves," from cata- "among" + tumbas, accusative plural of tumba "tomb" (see tomb).
If so, the word perhaps was altered by influence of Latin -cumbere "to lie." From the same source are French catacombe, Italian catacomba, Spanish catacumba. Extended by 1836 in English to any subterranean receptacle of the dead (as in Paris). Related: Catacumbal.
"empty tomb erected in honor of a dead person who is buried elsewhere or whose body is lost," c. 1600, from French cénotaphe (16c.), from Latin cenotaphium, from Greek kenotaphion, from kenos "empty" (see keno-) + taphos "tomb, burial, funeral," related to taphē "interment," thaptō "to bury," which is of uncertain origin. It is traditionally derived (along with Armenian damban "tomb") from a PIE root *dhembh- "to dig, bury," but there are doubts, and Beekes writes, "Armenian and Greek could well be borrowings; IE origin is uncertain." Related: Cenotaphic.
"study of the means by which the remains of living beings become fossils," 1940, with -nomy
+ Greek taphos "tomb, burial, funeral," which is of uncertain origin. It is traditionally derived (along with Armenian damban "tomb") from a PIE root *dhembh- "to dig, bury," but there are doubts, and Beekes writes, "Armenian and Greek could well be borrowings; IE origin is uncertain." Related: Taphonomic.