pillar in WordNet English dictionary

1. (architecture) a tall vertical cylindrical structure standing upright and used to support a structure
   column  pillar 
   
2. a vertical cylindrical structure standing alone and not supporting anything (such as a monument)
   column  pillar 
   
3. anything that approximates the shape of a column or tower
   "the test tube held a column of white powder"; "a tower of dust rose above the horizon"; "a thin pillar of smoke betrayed their campsite"
   column  tower  pillar 
   
4. a prominent supporter
   "he is a pillar of the community"
   pillar  mainstay 
   
5. a fundamental principle or practice
   "science eroded the pillars of superstition"
   pillar