- ravine formation
- ray
- re-cap
- re-grinding
- re-tarring
- reach conjugation
- reaction couple
- reaction modulus
- reactivity
- ready prompt
- rear
- rear mounting
- reassigning
- rebating
- rebuild
- rebuke
- recall
- recapping machine
- receiver autodyne
- receiving hopper
- reception area
- reception room
- receptor
- reciprocal deflection
- reciprocal displacement
- reciprocal theorem
- recirculated product
- reclamation
- rainproof canopy
- rainwater head
- rainwater pipe
- raised panel
- raked joint
- raker
- raking arch
- raking flashing
- raking riser
- rammer
- ramp bridge
- random failure
- range
- range point
- rapid information
- rarefaction
- raster
- rated speed
- ratiometer
- rational mechanics
- rationalize
- raw material
- raw meal
- raw mix
- raw peat
- raw stuff
- Raymond pile
- reaction isobar
- reaction time
- reader
- real estate
- real grab
- real stress
- real work
- realize
- ream
- reamer
- rearrangement
- reassemble
- rebore
- receiving chute
- receiving set
- recently
- reception
- reception office
- recessed corner
- recharge basin
- recharge well
- reciprocal
- reciprocal constraint
- reclaim
- recoding
- recompilation
- reconnaissance
- reconstruction
- reconstruction work
- reconstruction zone
- record
- record set
- recorder
- recording barometer
- recording scale
- recount
- recover
- recovered dust
- recovery peg
- recovery room
- recovery time
- recreation
- recreation area
- recreation gallery
- recreation room