'pillar' originates from Old French 'pilier', ultimately from Late Latin 'pillāris' (from Latin 'pila'), where 'pila' meant 'a pillar or column.'

'pillar' changed from Old French 'pilier' and Middle English forms (e.g. 'piler') and eventually became the modern English word 'pillar'.

Initially, it referred primarily to a physical column or post; over time it also developed figurative meanings such as 'a main support or important person.'