Split air conditioner is another term for a central air conditioner. Mini-split air conditioner is another term for a ductless air conditioner. The term split air conditioner comes from the fact that a central air conditioning system actually has two separate major components: the outdoor unit most people think of AND the indoor evaporator coil that connects to the furnace and uses the furnace’s fan. A mini-split system or a ductless mini-split system is essentially a type of air conditioner which is usually made to cool somewhat smaller areas, rather than an entire home, and the outdoor unit itself is also usually a bit smaller. Hence the name mini-split.