Wiktionary
cyclobutanone
n. (context organic compound English) The ketone derived from cyclobutane; any derivative of this compound
Wikipedia
Cyclobutanone
Cyclobutanone is an organic compound with molecular formula CHO. It is a four-membered cyclic ketone (cycloalkanone). Unlike cyclopropanone, the smallest but extremely volatile cyclic ketone, cyclobutanone is a stable liquid at room temperature and can be distilled.