pillar
n. countablen. a tall, strong post that holds up a roof or a bridge. It can also describe a person or idea that is a very important part of something.
n. a vertical structural member used to support a weight or to serve as a monument; figuratively, a person or principle providing essential support for a system or organization.
The heavy stone roof is supported by four marble pillars.
She has been a pillar of the local community for over thirty years, volunteering at the library every weekend.
The legal system rests on the pillar of impartial justice, without which the entire framework of democratic governance would eventually collapse under the weight of corruption.
From Middle English piler, from Old French pilier, from Medieval Latin or Vulgar Latin *pilāre (“a pillar”), from Latin pila (“a pillar, pier, mole”).
Often used figuratively in the phrase 'a pillar of' followed by a community, society, or institution.