mesopelagic

[mez-uh-puh-laj-ik, mes-, mee-zuh-, -suh-]
adjective Oceanography.
  1. of, relating to, or living in the ocean at a depth of between 600 feet (180 meters) and 3000 feet (900 meters).

Origin of mesopelagic

First recorded in 1945–50; meso- + pelagic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for mesopelagic

mesopelagic

adjective
  1. of, relating to, or inhabiting the intermediate depths of the ocean between approximately 100 and 1000 metres
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