epitaph: [14] Greek táphos meant ‘tomb’, and so an oration that was epitáphios (an adjective formed with the prefix epí- ‘over’) was given ‘over the tomb’. Eventually the adjective was made into a noun, epitáphion, and this reached English via Latin epitaphium and Old French epitaphe.
epitaph (n.)
"inscription on a tomb or monument," mid-14c., from Old French epitaphe (12c.) and directly from Medieval Latin epitaphium "funeral oration, eulogy," from Greek epitaphion "a funeral oration," noun use of neuter of epitaphios (logos) "(words) spoken on the occasion of a funeral," from epi "at, over" (see epi-) + taphos "tomb, funeral rites," from PIE root *dhembh- "to bury." Related: Epitaphial. Among the Old English equivalents was byrgelsleoð.