Definition of petrography
: the description and systematic classification of rocks
Love words? Need even more definitions?Merriam-Webster unabridged
Words at Play
Ask the Editors
Commonly Confused Words Quiz
Take a (break/brake) and (pore/pour) over this (c...
Words Named After People
Find out who’s behind "leotard," "morphine," an...
How Strong Is Your Vocabulary?
Test your vocabulary with our 10-question quiz!
Spelling Bee Quiz
Can you outdo past winners of the National Spelli...