Borrowing from French de rigueur (“required”), from de (“of”) + rigueur (“rigour/rigor”).
- Necessary according to etiquette, protocol or fashion.
- Wearing a suit to a job interview is de rigueur.
- This season, the little black dress is de rigueur.
- Spelling: there is a u immediately after the g as well as after the e.
- As this is a borrowed foreign phrase, it is often italicised (as de rigueur).
necessary according to etiquette