Dictionary.com
definitions

subduction

[suh b-duhk-shuh n]
noun
  1. an act or instance of subducting; subtraction or withdrawal.
  2. Geology. the process by which collision of the earth's crustal plates results in one plate's being drawn down or overridden by another, localized along the juncture (subduction zone) of two plates.

Origin of subduction

1570–80; < Latin subductiōn-, stem of subductiō pulling up, computation; see subduct, -ion
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for subduction zone

subduction zone

noun
  1. geology a long narrow, often arcuate, zone along which subduction takes place

subduction

noun
  1. the act of subducting, esp of turning the eye downwards
  2. geology the process of one tectonic plate sliding under another, resulting in tensions and faulting in the earth's crust, with earthquakes and volcanic eruptions
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for subduction zone

subduction

n.

early 15c., "withdrawal, removal" (originally of noxious substances from the body), from Latin subductionem (nominative subductio), noun of action from past participle stem of subducere (see subduce). Geological sense is attested from 1970, from French (1951).

Online Etymology Dictionary, © 2010 Douglas Harper
subduction zone in Science

subduction zone

  1. A convergent plate boundary where one plate subducts beneath the other, usually because it is denser. The western coast of South America is roughly coincident with a subduction zone in which a plate consisting of ocean floor is subducting beneath the continental mass of South America.

subduction

[səb-dŭk′shən]
  1. A geologic process in which one edge of one lithospheric plate is forced below the edge of another. The denser of the two plates sinks beneath the other. As it descends, the plate often generates seismic and volcanic activity (from melting and upward migration of magma) in the overriding plate. Compare obduction.
Related formssubduct verb
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.