ketone body

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A ketone-containing substance, such as acetoacetic acid, that is an intermediate product of fatty acid metabolism. Ketone bodies tend to accumulate in the blood and urine of individuals affected by starvation or uncontrolled diabetes mellitus. Also called acetone body.

Wiktionary

1. n. biochemistry Any of several compounds that are intermediates in the metabolism of fatty acids; principally acetoacetate and acetone (together with hydroxybutyrate which is not a ketone)

WordNet 3.0

1. n. a ketone that is an intermediate product of the breakdown of fats in the body; any of three compounds (acetoacetic acid, acetone, and/or beta-hydroxybutyric acid) found in excess in blood and urine of persons with metabolic disorders