礼服 (lǐ fú): ceremonial robe; formal attire (dinner suit, evening gown etc)

A month before the wedding, she visited several shops and finally found a well-fitting white gown.

The musicians of the symphony orchestra all have to wear black formal attire for tonight's performance.

At the graduation ball, wearing a rented tuxedo, he nervously asked her to dance.

This hotel requires guests to wear formal attire for dinner; shorts and slippers are not allowed inside.

At the awards ceremony, she walked onto the stage in a long red gown, catching everyone's attention.