A whip is an official in a political party whose primary purpose is to ensure party discipline in a legislature. Whips are a party's "enforcers", who typically offer inducements and threaten punishments for party members to ensure that they vote according to the official party policy. A whip's role is also to ensure that the elected representatives of their party are in attendance when important votes are taken. The usage comes from the hunting term whipping in, i.e. preventing hounds from wandering away from the pack.
The term "whip" is also used to mean:
In the Parliament of Australia, as well as in the parliaments of the five states and two self-governing territories, all political parties have whips to ensure party discipline and carry out a variety of other functions on behalf of the party leadership. The most important function of the whip's office is to ensure that all members and senators are present to take part in votes in the chamber (maintaining quorum and preventing censure motions). Unlike in the United Kingdom, Australian whips do not hold official office, but they are recognised for parliamentary purposes. In practice, Australian whips play a lesser role than their counterparts in the United Kingdom, as party discipline in Australia tends to be tighter.