Kitty refers to the amount collected at the party. Every member contributing a certain sum of money a month. The kitty is handed over to one member of the group every month. The chit funds operate along similar principles.
It is usually held at a specified time each month, by a specific group of women. Every member of the group has to host a party at least once. The hosting member organises food and other logistics, and the party is usually a gossiping place for women. In most of Pakistan, it is usually simply referred to as a 'committee'.
The party is held in the afternoons, usually on a monthly basis. It can be for any amount.