1. Suppressing or eliminating engine knock in combustion engines
   - antiknock

See also: leaded

• ridgling
• ridgy
• ridicule
• ridiculer
• ridiculous
• ridiculously
• ridiculousness
• riding
• riding bitt
• riding boot
• riding breeches
• riding crop
• riding habit
• riding horse
• riding lamp
• riding light
• riding master
• riding mower
• riding school
• ridley
• ridotto
• riel
• Riemann
• Riemannian
• Riemannian geometry