- a combining form meaning “rock,” “stone,” used in the formation of compound words: petrology.
Origin of petro-1
< Greek, combining form of pétra rock, pétros a stone
- a combining form meaning “petroleum,” “the extraction and export of petroleum,” used in the formation of compound words: petrochemistry; petropower.
Origin of petro-2
extracted from petroleum
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
before a vowel petr-
- indicating stone or rockpetrology
- indicating petroleum, its products, etcpetrochemical
- of or relating to a petroleum-producing countrypetrostate
from Greek petra rock or petros stone
Word Origin and History for petro-
before vowels petr-, word-forming element used from 19c., from comb. form of Greek petros "stone," petra "rock" (see petrous).
word-forming element used from mid-20c. to mean "of or having to do with petroleum products," from petroleum.
Online Etymology Dictionary, © 2010 Douglas Harper
- Rock; stone; stone-like hardness:petrous.