Definition of "antiknock" [antiknock]

• A substance, such as tetraethyl lead, added to gasoline to reduce engine knock. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "They replaced the last of the lead-like antiknock with ethanol in big part due toADM."
• "Distillate fuels and heavy oils were heated under pressure in large drums until they cracked into smaller molecules with better antiknock characteristics."
• "Moreover, cracked gasoline actually had a much better antiknock value than natural gasoline, which meant more power and allowed for higher-compression engines."