Dictionary.com
definitions

anesthesiologist

or an·aes·the·si·ol·o·gist

[an-uh s-thee-zee-ol-uh-jist]
noun
  1. a physician who specializes in anesthesiology.

Origin of anesthesiologist

First recorded in 1940–45; anesthesiolog(y) + -ist

anaesthesiology

[an-uh s-thee-zee-ol-uh-jee]
noun
  1. anesthesiology.
Related formsan·aes·the·si·ol·o·gist, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for anaesthesiologist

anaesthesiology

US anesthesiology

noun
  1. the US name for anaesthetics

anesthesiologist

anaesthesiologist

noun
  1. the US name for anaesthetist Compare anesthetist
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
Word Origin and History for anaesthesiologist
n.

1943, American English, from anaesthesiology + -ist.

anesthesiologist

n.

alternative spelling of anaesthesiologist (q.v.). See ae.

anaesthesiology

n.

1908, from anaesthesia + -ology.

Anesthesiology. This is the new term adopted by the University of Illinois defining "the science that treats of the means and methods of producing in man or animal various degrees of insensibility with or without hypnosis." ["Medical Herald," January, 1912]
Online Etymology Dictionary, © 2010 Douglas Harper