A pillar is a strong, vertical support that holds up a structure or building. It can also be used metaphorically to mean a vital or important part of something. Full definition
Investing — along with growing your income and saving — should be a key pillar in your wealth - building strategy. (investmentzen.com)
For a romantic glow overhead, group various sizes of pillar candles on a metal disk suspended by chains. (bhg.com)
In other words, the theory that is itself the most important supporting pillar for the modernist system is itself supported by that very system, in a classic example of circular reasoning. (firstthings.com)