1. Pertaining to the action of something moving or happening with great speed and force: The rapid pace of the river challenged the kayakers during their journey down the river.
2. A reference to something taking place within a short time or quickly: With the heavy rainfall, the rapid growth of the forest was predictable.
3. Descriptive of moving or acting with great speed: Because of her rapid skills in sorting the tray of polished stones, the new worker, Janet, earned a bonus in her pay.
4. Characterized by speed: The rapid gesture of the swordsman distracted his opponent during the competition and that’s how Tom won the contest.
5. Etymology: rapid is traced back to 1634, from Latin rapidus, "hasty, snatching", from rapere, "hurry away, carry off, seize, plunder" (related to Greek ereptomai, "devour"; harpazein "snatch away").

Rapids is from 1765, from French rapides, applied by French voyagers to North American rivers.

Like "rape" and "rapture", rapid came ultimately from Latin rapere, "seize by force". From this was derived the adjective rapidus, which originally indicated "carrying off by force".

The notion of "swiftness" soon became incorporated into the meaning and although the Latin adjective retained its original connotations of "violence" (it suggested "impetuous speed" or "haste); by the time it reached English, it had simply become synonymous with "quick" or "fast".