Saturday night1
/ˌsatədeɪ ˈnʌɪt/ /ˌsatədi ˈnʌɪt/noun
The night of Saturday.
- Traditionally a time for recreation and social events because the next day is not a working day..
Origin
Late 15th century; earliest use found in William Caxton (1415x24–1492), printer, merchant, and diplomat. From Saturday + night.
Saturday-night2
/ˌsatədeɪˈnʌɪt/ /ˌsatədiˈnʌɪt/verb
[no object] To spend a Saturday night in enjoyment or revelling; to go out socially on a Saturday night. Also with object with it. specifically (of a singer, performer, etc.) to perform at a club or other venue on a Saturday night (now rare ).
Origin
1930s; earliest use found in The Modesto Bee. From Saturday night.