res·pi·ra·to·ry 
(rĕspər-ə-tôr′ē, rĭ-spīrə-)
(rĕspər-ə-tôr′ē, rĭ-spīrə-)adj.
Of, relating to, used in, or affecting respiration.
- observatory
- observe
- observer
- observingly
- obsess
- obsession
- obsessional
- obsessionally
- obsessive
- obsessive-compulsive
- obsessive-compulsive disorder
- obsessive-compulsive personality disorder
- obsessively
- obsessiveness
- obsessor
- obsidian
- obsolesce
- obsolescence
- obsolescent
- obsolescently
- obsolete
- obsoletely
- obsoleteness
- obsoletism
- obstacle