from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Moving, acting, or occurring with great speed. See Synonyms at fast1.
  • n. An extremely fast-moving part of a river, caused by a steep descent in the riverbed. Often used in the plural.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Describes a process or concept which occurs quickly.
  • n. a rough section of a river or stream which is difficult to navigate due to the swift and turbulent motion of the water.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Very swift or quick; moving with celerity; fast
  • adj. Advancing with haste or speed; speedy in progression; in quick sequence
  • adj. Quick in execution.
  • n. The part of a river where the current moves with great swiftness, but without actual waterfall or cascade; sometimes called whitewater; -- usually used in the plural.

from The Century Dictionary and Cyclopedia

  • Moving or doing swiftly or with celerity; acting or performing with speed; quick in motion or execution: as, a rapid horse; a rapid worker or speaker.
  • Swiftly advancing; going on or forward at a fast rate; making quick progress: as, rapid growth; rapid improvement; a rapid conflagration.
  • Marked by swiftness of motion or action; proceeding or performed with velocity; executed speedily.
  • Gay.
  • =Syn. 1–3. Fast, fleet, expeditious, hasty, hurried.
  • n. A swift current in a river, where the channel is descending; a part of a river where the current runs with more than its ordinary celerity; a sudden descent of the surface of a stream, more or less broken by obstructions, but without actual cataract or cascade: usually in the plural.
  • In photography, said of plates, lenses, and subjects which require short exposure or print rapidly.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. done or occurring in a brief period of time
  • adj. characterized by speed; moving with or capable of moving with high speed
  • n. a part of a river where the current is very fast


Latin rapidus, from rapere, to seize.
(American Heritage® Dictionary of the English Language, Fourth Edition)
Latin rapidus (Wiktionary)



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