allochthon

noun

al·​loch·​thon

əˈläkthən,

aˈ-,

-ˌthän

variants or allochthone

-ˌthōn

plural -s

: an overthrust block of rocks that have been moved along a fault for a great distance from their place of origin

Word History

Etymology

back-formation from allochthonous

First Known Use

1931, in the meaning defined above

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