Dictionary.com
definitions

decerebrate

[verb dee-ser-uh-breyt; noun dee-ser-uh-breyt, -brit]
verb (used with object), de·cer·e·brat·ed, de·cer·e·brat·ing.
  1. Surgery. to remove the cerebrum.
noun
  1. a decerebrated animal.
  2. a person who, because of brain injury, exhibits behavior characteristic of a decerebrated animal.

Origin of decerebrate

First recorded in 1895–1900; de- + cerebr- + -ate1
Related formsde·cer·e·bra·tion, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for decerebration

decerebrate

verb (diːˈsɛrɪˌbreɪt)
  1. (tr) to remove the brain or a large section of the brain or to cut the spinal cord at the level of the brain stem of (a person or animal)
noun (diːˈsɛrɪbrɪt)
  1. a decerebrated individual
Derived Formsdecerebration, noun

Word Origin for decerebrate

C19: from de- + cerebro- + -ate 1
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
decerebration in Medicine

decerebration

[dē-sĕr′ə-brā′shən]
n.
  1. The elimination of cerebral function in an animal by removing the cerebrum, cutting across the brainstem, or severing certain arteries in the brainstem, as may be done for experimentation.

decerebrate

[dē-sĕr′ə-brāt′, -brĭt]
adj.
  1. Of, relating to, or characteristic of an individual who has suffered a brain injury that results in neurological function comparable to that resulting from decerebration of an animal.
v.
  1. To eliminate cerebral brain function in an animal by decerebration.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.