From Longman Dictionary of Contemporary Englishsingalongsing‧a‧long /ˈsɪŋəlɒŋ $ -lɒːŋ/ noun [countable] DLSINGan informal occasion when people sing songs together SYN singsong British English
Examples from the Corpus
singalong• Perfect for a singalong on the barricades.• Catchy tunes, though, and everyone had a singalong.• There were more than fourteen acts, from stand-up comics to bawdy singalongs.• But he does honestly like them and can join a playground game or a classroom singalong without a hint of embarrassment. 