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.
- white hole
- white hope
- Whitehorse
- white-hot
- White House
- white iron pyrites
- white knight
- white-knuckle
- white-knuckled
- white lead
- white lie
- white light
- white lightning
- whitelist
- white-livered
- white magic
- white mahogany
- Whiteman
- white man's burden
- white marlin
- white matter
- white meat
- white metal
- white mica
- White Mountains