À la mode
Fashionable. Also, in the USA, a dessert served with ice cream.
This, of course, has a French origin and is one of the earliest French phrases to have been adopted into English. It is referred to in John Selden's Laws of England, 1649:
"Commanders that are never a-la-mode but when all in Iron and Steel."
The term was anglicised as a noun - alamode, which was a form of glossy black silk. This is listed in a 1676 edition of The London Gazette:
"Several Pieces of wrought Silk, as Taffaties, Sarcenets, Alamodes, and Lutes."
Americans are familiar with this phrase as meaning 'with ice cream'. There are various stories concerning how this came about but, as they aren't reliably documented, I'll not repeat them here. Suffice it to say that, however the phrase was coined in that context, it had happened by 1903 when it appears in an edition of Everybody's Magazine:
"Tea and buns, apple pie à la mode and chocolate were the most serious menus."
See also - other French phrases in English.