Their discovery: cotton pajamas, which they're wearing for informal evenings.
There are formal, dress-up nights as well as informal, casual evenings.
After that, there was a required appearance at supper in the great hall that evening, informal but still requiring him to be on show.
It was that sort of thing a quiet informal evening.
After the show, a number of women called the cardigan their favorite style for informal evenings.
Here is a quiet, moving, informal evening of theater.
It's just an informal evening at The Palm with a client and his wife.
Her bare arms were creamy outlines against the dark informal evening.
In May 1952 the first "informal evening of opera" was presented and well received.
It was a most happy, graciously informal evening, with friends from both sides of the Atlantic.