- the upward movement of rocks on one side of a fault plane relative to rocks on the other side
WordReference Random House Unabridged Dictionary of American English © 2026
up•throw
(n. up′thrō′;v. up thrō′),USA pronunciation n., v., -threw, -thrown, -throw•ing.
n.
v.t.
n.
- an upheaval, as of the earth's surface.
- Geologyan upward displacement of rock on one side of a fault.
v.t.
- to throw or cast up or upward.
- up- + throw 1590–1600
Collins Concise English Dictionary © HarperCollins Publishers::
upthrow /ˈʌpˌθrəʊ/ n