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[in-fil-trey-shuh n] /ˌɪn fɪlˈtreɪ ʃən/
the act or process of infiltrating.
the state of being infiltrated.
something that infiltrates; an infiltrate.
  1. a method of attack in which small bodies of soldiers or individual soldiers penetrate the enemy's line at weak or unguarded points in order to assemble behind the enemy position and attack it from the rear, harass enemy rear-area installations, etc.
  2. a system of transporting troops or vehicles at extended and irregular intervals so as to avoid enemy observation or attack, especially from the air.
Geology. the seepage of water into soil or rock.
Compare percolation (def 3).
Origin of infiltration
First recorded in 1790-1800; infiltrate + -ion
Related forms
reinfiltration, noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Contemporary definitions for infiltration's 21st Century Lexicon
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Word Origin and History for infiltration

early 15c., "a knitting together," noun of action from infiltrate. In physics, from 1796. Figurative sense of "a passing into" (anything immaterial) is from 1840; military sense of "stealthy penetration of enemy lines" dates from 1930.

Online Etymology Dictionary, © 2010 Douglas Harper
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infiltration in Medicine

infiltration in·fil·tra·tion (ĭn'fĭl-trā'shən)

  1. The act or process of infiltrating.

  2. The state of being infiltrated.

  3. The gas, fluid, or dissolved matter that has entered a substance, cell, or tissue.

in·fil'tra·tive (-trə-tĭv) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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