1520s, "hasten the occurrence of;" 1590s, "make quicker" (implied in accelerating), from Latin acceleratus, past participle of accelerare "to hasten, quicken" (trans.), "make haste" (intrans.), from ad "to" (see ad-) + celerare "hasten," from celer "swift," which is perhaps from PIE *keli- "speeding" (see celerity). The intransitive sense of "go faster, become faster" in English is from 1640s. Related: Accelerated; accelerative.
"act or condition of going faster," 1530s, from Latin accelerationem (nominative acceleratio) "a hastening," noun of action from past-participle stem of accelerare "to hasten, quicken," from ad "to" (see ad-) + celerare "hasten," from celer "swift," which is perhaps from PIE *keli- "speeding" (see celerity).
"hasten along, move precipitately," 1810, perhaps from hurry-scurry (1732), a reduplication of hurry (v.), or imitative. As a noun, "a hurried movement, fluttering or bustling haste," 1823, from the verb.
musical instruction indicating a passage to be played with gradually increasing speed, 1842, from Italian accelerando, present participle of accelerare, from Latin accelerare "to hasten, quicken" (see accelerate).
in the philosophical sense of "voluntary agency" (embracing desire and volition), 1836, from Latin conationem (nominative conatio) "an endeavoring, effort," noun of action from past participle stem of conari "to endeavor, to try," from PIE *kona-, from root *ken- "to hasten, set oneself in motion" (see deacon).