Origin and history of upshift

c. 1300, "a movement, a beginning," from shift (v.); by mid-15c. as "an attempt, expedient, or means." This is the word in make shift "make efforts" (mid-15c.; see makeshift). The specific sense of "means to an end" is from 1520s, hence "a device, a trick." The sense of "change, alteration" in character, place, position, etc., is from 1560s.

The meaning "mechanism for changing gear in a motor vehicle" is recorded from 1914. Typewriter shift key is so called by 1893; its shift-lock is so called from 1899.

The meaning "period of working time" (originally in a mine) is attested from 1809, perhaps from or influenced by an older sense "relay of horses" (1708); perhaps also influenced by a North Sea Germanic cognate word (such as North Frisian skeft "division, stratum," skaft "one of successive parties of workmen"). Similar double senses of "division" and "relay of workers" is in Swedish skift, German schicht.

c. 1300, "dwelling inland or upland," from up (adv.). It is attested by late 14c. as "having risen from bed" and 1530s as "not yet gone to bed." The meaning "going up" is from 1784 in reference to trains, coaches, etc.; by 1948 of elevators.

It is attested from 1815 as "excited, exhilarated, happy," hence "enthusiastic, optimistic." In baseball, "at bat," by 1896. From the adverb in the sense of "so as not to fall short (of), keeping even with" (1510s) as in catch up, keep up in a race, etc., comes the extended senses of "in a condition to understand; well equipped with experience and skill." Up-and-coming "promising" is from 1848 (compare upcoming). Musical up-tempo (adj.) is recorded from 1948.