"four-footed reptile with the trunk naturally encased in a 'shell' of bony plates," 1550s, tortoyse, an altered spelling (perhaps by influence of porpoise) of tortuse, turtuse (late 14c., c.1200 in surnames), tortuce (early 15c.), tortuge (late 14c.), all from Medieval Latin tortuca (mid-13c.).

This is perhaps from Late Latin tartaruchus "of the underworld" (see Tartarus). Others propose a source in Latin tortus "twisted," based on the shape of the feet. The classical Latin word was testudo, from testa "shell." Probably originally applied to some land tortoise of southern Europe.

The word has undergone extraordinary variations of form, the latest being that which appears in tortle, now turtle .... [Century Dictionary]

Tortoise shell is attested from c. 1600 as "shell of a sea-turtle," used extensively in ornamental work; as a mottled pattern of black and gold markings, from 1782; in reference to a cat of this coloring by 1791.

"sweet cake, tart," 1748, from German Torte; earlier sense of "round cake, round bread" (1550s) is from French torte; both are from Late Latin torta "flat cake," also "round loaf of bread" (also source of Italian torte, Spanish torta), thus it probably is related to tart (n.1). Not considered to be from the source of tort. Torteau and tortel are French diminutives which also have been served up in English.

also tortfeasor, in law, "wrongdoer, trespasser," literally "committer of a tort" in the old sense; 1650s, from Old French tortfesor, from tort "wrong, evil" (see tort) + -fesor "doer," from Latin facere "to make, do" (from PIE root *dhe- "to set, put").

late 14c., torcious, "wrongful, illegal, injurious, harmful," from Anglo-French torcious (14c.), from stem of torcion, literally "a twisting," from Late Latin tortionem (see torsion, and compare tort). The meaning "pertaining to a tort" is from 1540s.

Proto-Indo-European root meaning "to twist."

It might form all or part of: contort; distort; extort; extortion; nasturtium; queer; retort; thwart; torch; torment; torque (n.) "rotating force;" torsion; tort; torticollis; tortuous; torture; truss.

It might also be the source of: Sanskrit tarkuh "spindle;" Latin torquere "to twist;" Old Church Slavonic traku "band, girdle;" Old High German drahsil "turner," German drechseln "to turn on a lathe;" Old Norse þvert "across," Old English þweorh "transverse, perverse, angry, cross," Gothic þwairhs "angry."