What does CLMN(S) stand for?

Column

The duct work installed to bring fresh, outside air to the furnace and/or hot water heater. Normally 2 separate supplies of air are brought in: One high and One low. Or Free standing vertical load bearing member or Is a main vertical member carrying axial loads, which can be combined with bending and shear, from the main roof beams or girders to the foundation. These structural members carry loads parallel to its longitudinal axis. or A vertical structural compression member which supports loads.