Merriam-Webster's Collegiate Dictionary:
reddishness
rede
redear
redecorate
redecoration
redecorator
redeem
redeemable
redeemer
redeeming
redefine
redefinition
redemption
redemptioner
redemptive
redemptorist
redemptory
redeploy
redeployment
redescribe
redescription
redesign
redevelop
redeveloper
redevelopment
redeye gravy
redfish
redhead
redheaded
redhorse
redia
redial
redingote
redintegrate
redintegration
redintegrative
redirect
redirection
rediscount
rediscountable
redistribute
redistribution
redistributional
redistributionist
redistributive
redistrict
redivivus
redlands
redleg
redline
redly
redmond
redneck
rednecked
redness
redo
redolence
redolent
redolently
redon
redondo beach
redouble
redoubt
redoubtable
redoubtably
redound
redout
redox
redpoll
redress
redresser
redroot
redshank
redshift
redshifted
redshirt
redskin
redstart
redtail
redtop
reduce
reducer
reducibility
reducible
reducibly
reducing agent
reductant
reductase
reductio ad absurdum
reduction
reduction division
reduction gear
reductional
reductionism
reductionist
reductionistic
reductive
