Definitions of pillar:

• noun:   a fundamental principle or practice

  Example: "Science eroded the pillars of superstition"

• noun:   a prominent supporter

  Example: "He is a pillar of the community"

• noun:   (architeture) a tall cylindrical vertical upright and used to support a structure
• noun:   a vertical structure standing alone and not supporting anything (as a monument or a column of air)
• noun:   anything tall and thin approximating the shape of a column or tower

  Example: "A thin pillar of smoke betrayed their campsite"

• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #15084)