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adj. rap·id·er, rap·id·est
Moving, acting, or occurring with great speed. See Synonyms at fast1.
n. often rapids
An extremely fast-moving part of a river, caused by a steep descent in the riverbed.

[Latin rapidus, from rapere, to seize; see rep- in Indo-European roots.]

ra·pid′i·ty (rə-pĭd′ĭ-tē), rap′id·ness (răp′ĭd-nĕs) n.
rap′id·ly adv.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(rəˈpɪd ɪ ti)

also rap•id•ness

(ˈræp ɪd nɪs)

a rapid state or quality; swiftness.
[1610–20; < Latin rapiditās. See rapid, -ity]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.rapidity - a rate that is rapid
pace, rate - the relative speed of progress or change; "he lived at a fast pace"; "he works at a great rate"; "the pace of events accelerated"
fleetness - rapidity of movement; "fleetness of foot"
immediateness, instancy, instantaneousness, immediacy - the quickness of action or occurrence; "the immediacy of their response"; "the instancy of modern communication"
expeditiousness, despatch, dispatch, expedition - the property of being prompt and efficient; "it was done with dispatch"
promptitude, promptness - the characteristic of doing things without delay
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.


Collins Thesaurus of the English Language – Complete and Unabridged 2nd Edition. 2002 © HarperCollins Publishers 1995, 2002


The American Heritage® Roget's Thesaurus. Copyright © 2013, 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
hraîi, snarleiki


[rəˈpɪdɪtɪ] Nrapidez f
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005


[rəˈpɪdɪti] nrapidité f
Collins English/French Electronic Resource. © HarperCollins Publishers 2005


nSchnelligkeit f; (of action, movement also)Raschheit f; (of improvement, change, spread also)Rapidheit f; (of decline, rise)Steilheit f
Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007


[rəˈpɪdɪtɪ] nrapidità
Collins Italian Dictionary 1st Edition © HarperCollins Publishers 1995


(ˈrӕpid) adjective
quick; fast. He made some rapid calculations; He looked feverish and had a rapid pulse.
ˈrapidly adverb
raˈpidity noun
ˈrapidness noun
ˈrapids noun plural
a place in a river where the water flows quickly, often having dangerous rocks in mid-stream.
Kernerman English Multilingual Dictionary © 2006-2013 K Dictionaries Ltd.


n. rapidez, velocidad.
English-Spanish Medical Dictionary © Farlex 2012
References in classic literature ?
At each step the power of the winds and the waves increased, until, after a struggle of a few hours, the turbulent little billows succeeded in setting the whole field in motion, when it was driven beyond the reach of the eye, with a rapidity that was as magical as the change produced in the scene by this expulsion of the lingering remnant of winter.
As it meandered among rocks and precipices, they were frequently obliged to ford it, and such was its rapidity that the men were often in danger of being swept away.
During the eight months which were employed in the work of excavation the preparatory works of the casting had been carried on simultaneously with extreme rapidity. A stranger arriving at Stones Hill would have been surprised at the spectacle offered to his view.
The facts relating to this apparition (entered in various log-books) agreed in most respects as to the shape of the object or creature in question, the untiring rapidity of its movements, its surprising power of locomotion, and the peculiar life with which it seemed endowed.
Caught in these eddies of the atmosphere, it spun about with a rapidity that made their heads reel, while the car oscillated and swung to and fro violently at the same time.
On the present occasion it was in active operation; one piece of information following another with inconceivable rapidity.
Though several spaces of blue sky still parted the thick black clouds toward the horizon, a flock of fleecy vapors were advancing with great rapidity and drawing a light gray curtain from east to west.
Rapidity is the essence of war: take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots.
At first they seemed to be merely agitated as from the movement of some great body beneath the surface, and I at once conjectured that another submarine was rising to the surface in pursuit of us; but presently it became apparent that the level of the waters was rising, not with extreme rapidity, but very surely, and that soon they would overflow the sides of the pool and submerge the floor of the chamber.
Twenty leagues more, performed with the same rapidity, twenty more leagues devoured, and no one, not even D'Artagnan, could overtake the enemies of the king.
Miss Ladd's drawing-master was in that state of nervous irritability which seeks relief in rapidity of motion.
Barbicane took the paper, and began to make his calculations with great rapidity. Nicholl looked over and greedily read the work as it proceeded.