backstop (n.)
- advocate
- aegis
- back
- bank
- bar
- barrage
- barrier
- boom
- breakwater
- breastwork
- buffer
- bulkhead
- bulwark
- bumper
- champion
- cofferdam
- contraceptive
- copyright
- cushion
- dam
- dashboard
- defense
- dike
- ditch
- dodger
- earthwork
- embankment
- fence
- fender
- fuse
- gate
- goggles
- governor
- groin
- guard
- guardrail
- handrail
- helmet
- insulation
- interlock
- jam
- jetty
- levee
- lifeline
- logjam
- mask
- milldam
- moat
- mole
- mound
- mudguard
- pad
- padding
- palladium
- parapet
- patent
- pilot
- portcullis
- preventive
- prophylactic
- rampart
- roadblock
- safeguard
- safety
- screen
- seawall
- shield
- umbrella
- wall
- weir
- windscreen
- windshield
- work
