Conversation threading is a feature used by many email clients, , , and in which the software aids the user by visually grouping messages with their replies. These groups are called a conversation, topic thread, or simply a thread. A discussion forum, e-mail client or news client is said to have a "conversation view", "threaded topics" or a "threaded mode" if messages can be grouped in this manner.
In computer programming, a parameter is a special kind of variable, used in a subroutine to refer to one of the pieces of data provided as input to the subroutine. These pieces of data are called arguments. An ordered list of parameters is usually included in the definition of a subroutine, so that, each time the subroutine is called, its arguments for that call can be assigned to the corresponding parameters.