tractor n.

"area," mid-15c., "period or lapse of time," from Latin tractus "track, course, space, duration," lit, "a drawing out or pulling," from stem of trahere "to pull, draw," from PIE root *tragh- "to draw, drag, move" (source also of Slovenian trag "trace, track," Middle Irish tragud "ebb;" perhaps with a variant form *dhragh-; see drag (v.)). The meaning "stretch of land or water" is first recorded 1550s. Specific U.S. sense of "plot of land for development" is recorded from 1912; tract housing attested from 1953.

amphibious assault vehicle, 1944, contraction of amphibious tractor (n.).

1610s, "pertaining to movement," from French locomotif, from Latin loco "from a place" (ablative of locus "place;" see locus) + Late Latin motivus "moving" (see motive).

From 1650s as "moving from place to place;" by 1814 as "having the power of moving by itself. The noun meaning "engine which travels on rails by its own power" is from 1829, short for locomotive engine, which is attested from 1814. A locomotive engine used without rails was a traction engine, which became tractor.