en·dur·o 
(ĕn-drō, -dyrō)
(ĕn-drō, -dyrō)n. pl. en·dur·os
A race, as of motorcycles, that tests endurance.
[Shortening and alteration of ENDURANCE.]
- 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
- on welfare
- onycholysis
- onychomycosis
- onychophoran