What is "almack's"

Almack's Assembly Rooms was a social club in London from 1765 to 1871 and one of the first to admit both men and women. It was one of a limited number of upper class mixed-sex public social venues in the British capital in an era when the most important venues for the hectic social season were the grand houses of the aristocracy. From 1871 it was renamed "Willis's Rooms" (see below).