Learner's definition of PILLAR
1 : a large post that helps to hold up something (such as a roof) 2 : someone who is an important member of a group — + of 3 : a basic fact, idea, or principle of something — + of
a central pillar of the theory
one of the five pillars of Islam
The right to vote is a pillar of democracy.
4 : something that rises into the air in a tall, thin shape
from pillar to postchiefly British
: from one place or one situation to another
His book has been passed from pillar to post, but no one wants to publish it.
He has been running from pillar to post his whole life.
pillar of strength
: someone or something that gives support or help during difficult times