eu-

  1. a combining form meaning “good,” “well,” occurring chiefly in words of Greek origin (eupepsia); in scientific coinages, especially taxonomic names, it often has the sense “true, genuine” (eukaryote)

Origin of eu-

< Greek, combining form of eús good (adj.) or eú, eû (neuter, used as adv.) well
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for eu-

eu-

combining form
  1. well, pleasant, or goodeupeptic; euphony

Word Origin for eu-

via Latin from Greek, from eus good
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 eu-

word-forming element in modern use meaning "good, well," from comb. form of Greek eus "good," eu "well" (adv.), also "luckily, happily," from PIE *(e)su- "good" (cf. Sanskrit su- "good," Avestan hu- "good").

Online Etymology Dictionary, © 2010 Douglas Harper

eu- in Medicine

eu-

pref.
  1. Good; well; true:eupepsia.
  2. A derivative of a specified substance:euglobulin.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.