An octane number as determined by the research method of the American Society for Testing and Materials, used chiefly for low engine speeds and loads; abbreviated RON.
Origin
1940s; earliest use found in U.S. Patents.
Definition of research octane number in US English:
research octane number
noun
An octane number as determined by the research method of the American Society for Testing and Materials, used chiefly for low engine speeds and loads; abbreviated RON.