noun

an upright pillar, typically cylindrical, supporting an arch, entablature, or other structure or standing alone as a monument.

a wide entrance portico of eight Ionic columns

pillar,post,pole,support,upright,vertical,baluster,pier,pile,piling,pilaster,stanchion,standard,prop,buttress,rod,shaft,leg,mast,tower,pylon,obelisk,monolith,newel,caryatid,telamon,herm