Closed system

A system through whose boundary no energy enters or leaves.

A system across whose boundary no energy is transferred to or from the surroundings.

A group of interacting objects for which no external force changes the total momentum during the event.

A group of objects chosen for analysis; a closed system experiences no resultant external force during the interaction being considered.

A system in which, during the change being considered, there is no net transfer of energy across its boundary.

A system across whose boundary no energy is transferred, so its total energy remains constant.

A system from which matter cannot enter or escape.

A system through whose boundary energy may be transferred but matter cannot enter or leave.

A system into which no energy enters and from which no energy leaves.