antiknock

American  

[an-tee-nok, an-tahy-, an-tee-nok, an-tahy-] / ˌæn tiˈnɒk, ˌæn taɪ-, ˈæn tiˌnɒk, ˈæn taɪ- /

adjective

1. noting or pertaining to a substance, as tetraethyllead or ferrocene, used as a fuel additive for an internal-combustion engine to eliminate or minimize knock.

---

noun

1. such a substance added to fuel in an internal-combustion engine.

antiknock British  

/ ˌæntɪˈnɒk /

noun

1. a compound, such as lead tetraethyl, added to petrol to reduce knocking in the engine

---

Etymology

Origin of antiknock

First recorded in 1920–25; anti- + knock

Example Sentences

Modern engines not only don’t need lead but have sophisticated antiknock technologies that sense a fuel’s octane rating and adjust their ignition timing to prevent damage.

From New York Times