means A tall vertical support that bears the weight of a structure above it — or, by extension, a person or principle that something else fundamentally depends on.

from From Latin 'pila,' a stone pier or pillar, which softened through Medieval Latin 'pilare' into Old French 'piler' before settling into English. The same 'pila' is thought to lie behind 'pilaster' and possibly 'pile' in the sense of a heap of stones — fitting, for a word that has always been about stacking weight and making it stand.