From Longman Dictionary of Contemporary Englishhouseflyhouse‧fly /ˈhaʊsflaɪ/ noun (plural houseflies) [countable] HBIa common type of fly that lives in people’s houses
Examples from the Corpus
housefly• Thousands of individuals, each not quite as big as a housefly make up the swarm.• Even as I listened to him, mosquitoes, fat as houseflies, feasted on my legs.• Alice Foley, growing up in Bolton during the 1890s, remembered the plague of houseflies emanating from the privies in summer.• Cluster flies are bristly gray insects, about five times bigger than the ordinary housefly, Musca domestica. 