- concord
- concur
- condor
- conductor
- contort
- contour
- cord
- cordon
- corn
- court
- croc
- croon
- crouton
- crud
- curd
- curt
- doctor
- donor
- door
- dour
- nonconductor
- occur
- odor
- orotund
- outdoor
- outro
- outrun
- rococo
- rondo
- rood
- root
- rotor
- rotund
- round
- rout
- runout
- runt
- torn
- toro
- tort
- tour
- trod
- trot
- trout
- turn
- turnout
- tutor