once upon a time
a long time ago

[TahlilGaran] Dictionary of Contemporary English ▲

once upon a time
[literary]
1.
a long time ago.
Once upon a time there lived a young girl called Cinderella.

2.
if you say that something happened once upon a time, you mean that it happened in the past and you wish that it still happened now.
Once upon a time, everyone knew each other in this town and nobody bothered locking their doors.

[TahlilGaran] English Idioms Dictionary ▲

once upon a time
far in the past
Once upon a time a beautiful princess lived in a castle in a small town.

[TahlilGaran] English Idioms Dictionary ▲

once upon a time
adv. phr. Sometime before now, long ago.
Once upon a time she was thought to be the most talented actress in the country.
■ Often used at the beginning of fairy stories.
Once upon a time there lived a king who had an ugly daughter.

[TahlilGaran] English Idioms Dictionary ▲