-ˌchōn noun
( -s )
Etymology: German fenchon, from fenchel fennel + -on -one
: an oily terpenoid ketone C 10 H 16 O that is isomeric with camphor and has a camphoraceous odor, that exists in three optically different forms, occurring as the dextrorotatory form especially in fennel oil and as the levorotatory form in thuja oil, and that is used chiefly as a pine scent; 1,3,3-trimethyl-2-keto-norbornane