Merriam-Webster's Collegiate Dictionary:
resplendent
resplendently
respond
respondent
responder
response
responsibility
responsible
responsibleness
responsibly
responsions
responsive
responsively
responsiveness
responsory
responsum
ressentiment
rest
rest area
rest home
rest house
rest mass
restart
restartable
restate
restatement
restaurant
restauranteur
restaurateur
rested
restenosis
rester
restful
restfully
restfulness
resting
restitute
restitution
restive
restively
restiveness
restless
restless leg syndrome
restless legs
restless legs syndrome
restlessly
restlessness
reston
restorable
restoral
restoration
restorative
restore
restorer
restrain
restrainable
restrained
restrainedly
restrainer
restraining order
restraint
restrict
restricted
restrictedly
restriction
restriction endonuclease
restriction enzyme
restriction fragment length polymorphism
restrictionism
restrictionist
restrictive
restrictive clause
restrictively
restrictiveness
restrike
restroom
restructure
result
resultant
resultantly
resultful
resultless
resum?
resume
resumption
resupinate
resurface
resurfacer
resurgam
resurge
resurgence
resurgent
resurrect
resurrection
resurrectional
resurrectionist
resuscitate
