Air Handler - The portion of a central air conditioning or heat pump system that moves heated or cooled air throughout a homes ductwork.  In some systems, a furnace handles this function. 

Condensate - The water that results as a by-product of dehumidification.  Condensate is usually pumped out of the the unit via a condensate pipe into the drainage system.  Condensation occurs normally at your copper pipes coming from the air handler and sometimes underneath your CU.  Simply put, the water removed from your air when the air is cooled, or hot humid conditions can make condensate appear on your copper pipes from your air handler.

Condensing Unit (CU)  A condenser coil is one means of heat rejection commonly used in an air conditioning system.  It is typically located on an outdoor pad or on a rooftop and looks like an automobile radiator in a cabinet.  It is usually hot to the touch during normal use.  Its function is to transfer heat energy from the refrigerant to the cooler surrounding (usually outdoor) environment.  

Drain Pan-Collects "condensate" or water from your system and is then drained through the drain pipe.

Duct-A pipe or tube made from various materials, insulated and used to convey air.

Evaporator Coil -  The evaporator coil is an essential component used in the refrigeration cycle.  It looks like an automobile radiator.  This is the part of the system that gets cold to the touch during normal use.  Its usually found inside our home in a closet, or in the garage. 

Float Switch-Regulates the drainage from your drain pan.

Plenum - Any dedicated space that is used for the distribution or return of cooling air. 

Refrigerant-The working fluid used in the refrigeration cycle is know as the refrigerant.  The most commonly used refrigerant is R-22, however systems are converting to A-410 because of environmental issues.

SEER-  Cooling Efficiency.  "SEER" is a measure of cooling efficiency for air conditioning products.  SEER stands for Seasonal Energy Efficiency Ratings.  The higher the SEER rating number, the more energy efficient the unit.