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

See also: leaded

• achene
• achenial
• Acheron
• Acheronian
• Acherontia
• Acherontia atropos
• Acherontic
• Acheson
• Acheson process
• Acheta
• Acheta assimilis
• Acheta domestica
• achievability
• achievable
• achieve
• achievement
• achiever
• Achille Ratti
• achillea
• Achillea millefolium
• Achillea ptarmica
• Achilles
• Achilles tendon
• Achilles' heel
• achimenes