pe·trol·o·gy 
(pə-trŏlə-jē)
(pə-trŏlə-jē)n.
The branch of geology that deals with the origin, composition, structure, and alteration of rocks.
pet′ro·logic (pĕt′rə-lŏjĭk), pet′ro·logi·cal (-ĭ-kəl) adj.
pet′ro·logi·cal·ly adv.
pe·trolo·gist n.
- western
- Western Australia
- Western blot analysis
- Western Bug
- Western Dvina
- Western Empire
- westerner
- Western Europe
- Western Ghats
- Western Hemisphere
- Western Isles
- Western Isles
- westernization
- westernize
- westernmost
- westernness
- western omelet
- western red cedar
- Western Reserve
- Western Roman Empire
- Western Roman Empire
- western saddle
- Western Sahara
- Western Samoa
- western sandwich