- safety arch
- safety belt
- safety enclosure
- safety fence
- safety gate
- safety goggles
- safety guard
- safety precautions
- safety railing
- safety sign
- safety strip
- sag curve
- sag rod
- sagged glass
- sagging
- roofing
- roofing materials
- roofing paper
- roofing slate
- roofing tile
- room constant
- room cubage
- room height
- root timber
- rootdozer
- rope
- rope gasket
- rope holder
- ropiness
- rot pocket
- rotary blower
- rotary crusher
- rotary distributor
- rotary island
- rotary refrigerator
- rotary scarifier
- rotating screen
- rotation
- rotational speed
- rotunda
- rough bolt
- rough brick
- rough casting
- rough fracture
- rough logs
- rough survey
- rough wall
- rough-grained
- round arch
- round bars
- round figure
- round head
- round sand
- round section
- round trip
- round wedge
- rounded edge
- rounded grains
- route
- route factor
- route layout
- route survey
- roving
- row house
- rubber grain
- rubber hose
- rubber model
- rubber squeegee
- rubber tank
- rubberized asphalt
- rubble aggregate
- rubble backing
- rubble cushion
- ruling
- sale room
- salesroom
- saline basin
- saline soil
- salinity
- saloon
- salt bath
- salt dissolver
- salt impregnation
- salt lake
- salt mud
- salt production
- salt spreader
- salt-water
- saltbox
- saltern
- saltiness
- salty air
- salty dust
- salubrious
- salvage
- same
- samel brick
- sample
- sample collection
- sample divider