o·rol·o·gy 
(ô-rŏlə-jē)
(ô-rŏlə-jē)n.
The study of mountains.
o′ro·logi·cal (ôr′ə-lŏjĭ-kəl) adj.
o′ro·logi·cal·ly adv.
o·rolo·gist n.
- photoemission spectroscopy
- photoengrave
- photoengraver
- photoengraving
- photo-essay
- photo essay
- photo-essayist
- photo finish
- photoflash
- photoflood
- photofluorogram
- photofluorographic
- photofluorography
- photog
- photogelatin process
- photogene
- photogenic
- photogenically
- photogram
- photogrammetric
- photogrammetrist
- photogrammetry
- photograph
- photographable
- photographer