| petrogenesis (pět'rō-jěn'ĭ-sĭs) Pronunciation Key
The branch of petrology that deals with the origin and formation of rocks, especially igneous rocks. |
| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
| a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes. |