an evening social date on which a married or long-term couple go out together: I enjoy a once-a-week date night with my husband.
a night of the week on which it is usual or customary for couples to go out on a date: Saturday night is date night.
Origin of date night
First recorded in 1905–10
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019