[in-fil-trey-shuh n]


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).

Nearby words

  1. infield out,
  2. infielder,
  3. infighting,
  4. infill,
  5. infiltrate,
  6. infiltration anesthesia,
  7. infiltration capacity,
  8. infiltration gallery,
  9. infiltrator,
  10. infiltrometer

Origin of infiltration

First recorded in 1790–1800; infiltrate + -ion

Related formsre·in·fil·tra·tion, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for infiltration

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

Medicine definitions for infiltration




The act or process of infiltrating.
The state of being infiltrated.
The gas, fluid, or dissolved matter that has entered a substance, cell, or tissue.
Related formsin•filtra•tive (-trə-tĭv) adj.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.