(petrology) The branch of petrology that deals with the scientific description and classification of rocks. / The art of writing on stone.

An independent city in Virginia, United States. / A census-designated place, the borough seat of Petersburg Borough, Alaska. / A city, the county seat of Menard County, Illinois.

A substance, mostly carbon, that is a byproduct of oil refining; used as a fuel or in many industrial applications.

bad-tempered; peevish

(historical) A former department of the Court of Chancery that dealt with suits involving solicitors and officers of that court.

plural of Petri dish

Any form of racial segregation that applies only to public spaces.

(obsolete) Rudeness, insolence. / (obsolete) An insolent remark or act. / Childish impatience or sulkiness; testiness.

A geologist who specializes in petrology.

(geology) The study of the origin, composition and structure of rock.