a prefix occurring originally in loanwords from Greek, where it was joined to verbs, deverbal forms, and other parts of speech. Among its functions in Greek, apo- has the spatial sense “away, off, apart” (apogee; apocope; apostasy; apostrophe); it occurs with deverbals that denote a response or defense (apodosis; apology) and is found on verbs having perfective force relative to a corresponding simple verb (apoplexy; aposiopesis). In modern scientific coinages in English and other languages, apo- marks things that are detached, separate, or derivative (apocarpous; apoenzyme).

Nearby words

  1. apneustic,
  2. apneustic breathing,
  3. apnoea,
  4. apo,
  5. apo koinu,
  6. apoapsis,
  7. apoc.,
  8. apocalypse,
  9. apocalyptic,
  10. apocalypticism

Also especially before a vowel, ap-.

Origin of apo-

< Greek, prefixal use of apó; akin to off, Sanskrit apa, Latin ab

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for apo-




away from; offapogee
indicating separation ofapocarpous
indicating a lack or absence ofapogamy
indicating derivation from or relationship toapomorphine

Word Origin for apo-

from Greek apo away, off

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 apo-


before vowels ap-, word-forming element meaning "from, away from, separate, free from," from Greek apo "from, away from; after; in descent from," in compounds, "from, asunder, away, off; finishing, completing; ceasing from; back again," from PIE root *apo- "off, away" (cf. Sanskrit apa "away from," Avestan apa "away from," Latin ab "away from, from," Gothic af, Old English of "away from").

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for apo-



Away from; off:aponeurosis.
Without; lacking; not:apoferritin.
Related to; derived from:apomorphine.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.