ri·gid·i·ty 
(rĭ-jĭdĭ-tē)
(rĭ-jĭdĭ-tē)n. pl. ri·gid·i·ties
1. The quality or state of being rigid.
2. An instance of being rigid.
- ontogenetically
- ontogenic
- ontogenically
- ontogeny
- ontological
- ontologically
- ontologist
- ontology
- on top
- on top of
- on top of the world
- on trial
- on/under pain of
- on/upon(one's) hands
- on/upon (one's) hands
- on/upon request
- on/upon the heels of
- on uppers
- onus
- on view
- on vinyl
- on waivers
- onward
- on wax
- on way