Also especially before a vowel, proter-.
Compare proto-.

Origin of protero-

< Greek, combining form representing próteros, comparative formed from pró; see pro-2 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for protero-


combining form
  1. anterior or former in time, place, order, etcproterozoic

Word Origin for protero-

from Greek proteros fore
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 protero-

before vowels proter-, word-forming element meaning "former, earlier," from comb. form of Greek proteros "before, former, anterior," from PIE *pro-, from root *per- (1) "forward, through" (see per).

Online Etymology Dictionary, © 2010 Douglas Harper