terminus (n.)

"goal, end, final point," 1610s, from Latin terminus (plural termini) "an end, a limit, boundary line." This is reconstructed to be from PIE *ter-men- "peg, post," from root *ter-, base of words meaning "peg, post; boundary, marker, goal" (source also of Sanskrit tarati "passes over, crosses over," tarantah "sea;" Hittite tarma- "peg, nail," tarmaizzi "he limits;" Greek terma "boundary, end-point, limit," termon "border;" Gothic þairh, Old English þurh "through;" Old English þyrel "hole;" Old Norse þrömr "edge, chip, splinter").

"The Hittite noun and the usage in Latin suggest that the PIE word denoted a concrete object which came to refer to a boundary-stone." [de Vaan]

In ancient Rome, Terminus was the name of the deity who presided over boundaries and landmarks, often represented in half-statues or busts, and the focus of the important Roman festival of Terminalia (held Feb. 23, the end of the old Roman year). The meaning "either end of a transportation line" originally of a railway, is by 1836.