From Latin 'celer' (swift) via 'accelerare' — entered English in the 1520s as science needed words for motion.
To increase in speed, rate, or velocity; to cause something to happen sooner or more quickly.
From Latin 'acceleratus,' past participle of 'accelerare' (to hasten, to quicken), from 'ad-' (to, toward) + 'celerare' (to make fast), from 'celer' (swift, quick). Latin 'celer' derives from PIE *kel- (to drive, to set in swift motion), the same root that gives Greek 'kelēs' (a fast horse or racing vessel), and possibly Latin 'colere' (to cultivate, to till — to set in motion) and 'incitare' (to urge forward). English borrowed 'accelerate' in the 16th century in a general sense of hastening; the physical science meaning (rate of change of velocity) was formalised in the 17th century with Newtonian mechanics. The noun 'acceleration' arrived slightly before the verb. The root 'celer' also gives 'celerity' (swiftness), a formal synonym rarely used today. Key roots: ad- (Latin: "to, toward"), celer (Latin: "swift, quick"), *kel- (Proto-Indo-European: "to drive, set in motion").
The word 'celerity' — meaning swiftness — comes from the same Latin root 'celer' and was once common in English literary prose. Galileo's work on motion in the early 1600s helped popularize 'accelerate' as a technical term that eventually crossed into everyday speech.