sing-along

or sing·a·long

[ sing-uh-lawng, -long ]
/ ˈsɪŋ əˌlɔŋ, -ˌlɒŋ /

noun

an informal or unrehearsed singing of songs by a group of people, usually under the direction of a leader; songfest.
an occasion marked by such singing.

Origin of sing-along

First recorded in 1955–60; noun use of verb phrase sing along

British Dictionary definitions for sing along

sing along

verb (intr, adverb)

to join in singing with a performer

noun sing-along

such a singsong