1690s, from Late Latin tessellatus "made of small square stones or tiles," past participle of tesselare, from tessella "small square stone or tile," diminutive of tessera "a cube or square of stone or wood," perhaps from Greek tessera, neuter of tesseres, Ionic variant of tessares "four" (see four), in reference to four corners. Related: Tessellate (v.), a 1791 back-formation (from 1826 as an adjective, 1909 as a noun); tessellating.