an organic chemical compound containing the carbonyl group, CO, in combination with two hydrocarbon radicals
See ketone in American Heritage Dictionary 4
(kēˈtōnˌ)
noun
Any of a class of organic compounds, such as acetone, having a carbonyl group linked to a carbon atom in each of two hydrocarbon radicals and having the general formula R(CO)Rˌ, where R may be the same as Rˌ.