Chat is...
...a form of text-based electronic communication. Despite its name, chat is typed. Chats are held in virtual online "conference rooms" that can be accessed by users at any time, from anywhere. During a chat, messages typed by one user appear on the monitors of other users, who can then type responses. The give and take is synchronous and nearly instantaneous.
Chat is a quick, low-cost way to conduct meetings in a secured environment through the Internet. Typically, users connect with the chatroom using client software loaded on their personal computers. After logging into the virtual rooms, they communicate using their keyboards.