- rational analysis
- rational curve
- rational index
- rationality
- raw device
- raw mode
- ray
- rayon vecteur
- re-cap
- reaction front
- reactivation
- read access
- read amplifier
- read error
- read permission
- read rights
- read-only
- reader-interpreter
- reading point
- reading system
- README file
- ready indicator
- ready time
- Real
- real accumulator
- real domain
- real matrix
- real numbers
- real type
- reality
- recall
- recapping machine
- receive pacing
- receive state
- receiver register
- receiving field
- receiving margin
- receiving side
- receiving station
- receiving terminal
- recession
- reciprocal correspondence
- reciprocal kernel
- rainwater pipe
- RAM card
- ramification point
- random distribution
- random failure
- random marsonry
- random storage
- randomizing routine
- randomness
- range
- ranked element
- rapid growth
- rapid prototyping
- raster
- raster element
- raster pattern
- rated speed
- rating nut
- rating system
- ratio estimator
- ration surface
- rational expression
- rational invariant
- rational mechanics
- rationalize
- ray center
- re engineering
- reaction control
- reactivate
- read check
- read lock
- read operation
- read screen
- reader
- reading accuracy
- reading duration
- reading task
- real coefficients
- real file
- real line
- real plane
- real singularity
- real system
- reality check
- realization
- realized edge
- realm
- reamer
- rear compression
- reasonableness check
- rebore
- recalculation method
- receipt
- receive
- receiving data
- receiving set
- receiving system