morning suit
US /ˈmɔːr.nɪŋ ˌsuːt/
UK /ˈmɔːr.nɪŋ ˌsuːt/

1.
costume de ville, jaquette
a man's formal outfit for daytime wear, consisting of a tailcoat, waistcoat, and striped trousers
:
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He wore a traditional morning suit to the wedding.
Il portait un costume de ville traditionnel au mariage.
•
Guests were asked to wear a morning suit or equivalent formal attire.
Il a été demandé aux invités de porter un costume de ville ou une tenue de soirée équivalente.