Word Study
petro-
CIDE DICTIONARY
petro-,
A combining form from Gr. pe`tra a rock , pe`tros a stone ; as, petrology, petroglyphic. [1913 Webster]
OXFORD DICTIONARY
petro-, comb. form 1 rock.
2 petroleum (petrochemistry).
2 petroleum (petrochemistry).
Etymology
Gk petros stone or petra rock
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