'westerner' originates from English, formed from 'west' + adjectival suffix '-ern' and the agentive suffix '-er' (meaning 'person'). 'west' ultimately comes from Proto-Germanic '*westrą', from Proto-Indo-European '*wésr̥' meaning 'west'.

'westerner' developed from Middle English forms such as 'west' and 'westerne' (adjectival) with the later addition of '-er' to create a noun meaning 'person from the west', becoming established in Early Modern English.

Initially related to 'west' as an adjective ('western, of the west'), it later came to be used as a noun meaning 'a person from the West'; the modern core meaning is 'a person from the West'.