pillar

pillar /ˈpɪlɚ/ noun
plural pillars
pillar
/ˈpɪlɚ/
noun
plural pillars
Britannica Dictionary definition of PILLAR
[count]
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
4 
: something that rises into the air in a tall, thin shape

from pillar to post

chiefly British
: from one place or one situation to another

pillar of strength

: someone or something that gives support or help during difficult times