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(Geological Science) a long narrow steep-sided depression in the earth's oceanic crust, usually lying above a subduction zone
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
A deep, narrow trough in an ocean floor.
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