Origin and history of upstep

"a completed movement of the foot in walking," Old English steppa (Mercian), stæpe, stepe (West Saxon) "an act of stepping; a footprint," also "a stair, rung of a ladder," and by late Old English "manner of walking," from the source of step (v.). Compare Old Frisian, Middle Dutch, Dutch stap, Old High German stapfo, German Stapfe "footstep").

Also "distance traversed by a step" (mid-13c.), which led to the use of step as a unit of linear measure (late 13c.) equivalent to about 2.5 feet or a half-pace. In dancing, from 1670s. The specific meaning "type of military pace" is from 1798.

It is attested from late Old English as "degree on a scale, degree in progress or advance," in virtue, sin, etc. The notion is perhaps of a step as a support for the foot in ascending or descending. The figurative meaning "action which leads toward a result, a proceeding in a series of them" is recorded from 1540s.

The warning phrase watch your step is attested from 1911; Wycliffe (late 14c.) has keep thy foot in essentially the same sense. Step by step indicating steady progression is from 1580s. To follow in (someone's) steps "follow the example of" is from mid-13c.

a prefix bringing various senses of up, including "toward a more elevated position; at or to a source, head, or center; in or to an erect position;" originally from Old English up (adv.). It corresponds to Dutch op-, German auf-, Old Norse upp-.

Modern formations with it include upchuck, update, upfield, upgrade (v.), upload, upswing (n.), upscale, uptight, all from 20c.

The prefix was highly productive in Old and Middle English (and among poets of all eras), forming up-verbs where modern English uses "verb up." Some of these (uplift) survive.

Many do not: Upbear, upblaze, upblow, upbreak, updress, upgive, uphang, upshut, upsit, upspeak, uptie, upthrow, upwake, etc. The old verbs are not so much archaic as dissolved. In a few cases two forms survive to sustain (sometimes contrary) distinct senses: Hold up and uphold; set up and upset.