A ductless air conditioner or heater that is split between the outside and inside of a home. The outside portion often appears as a rectangular box with holes for exhausting heat. The inside portion of the unit is referred to as a head unit, wall unit, and/or evaporator. Minisplits have a variety of configurations: wall-mounted, ceiling-mounted, and in-floor.
This is a Minisplit head unit that is typically found mounted to an interior wall of a home: