Definition of "Pillar" :

noun: (architecture) a tall vertical cylindrical structure standing upright and used to support a structure

noun: a vertical cylindrical structure standing alone and not supporting anything (such as a monument)

noun: a fundamental principle or practice

"Science eroded the pillars of superstition."

noun: a prominent supporter

"He is a pillar of the community."

noun: anything that approximates the shape of a column or tower

"A thin pillar of smoke betrayed their campsite."