'washingtonia' originates from New Latin, specifically the name 'Washingtonia', where 'Washington' referred to the proper name 'Washington' (honoring George Washington) and the suffix '-ia' is a Latin-forming suffix used in taxonomy to create genus names.

'washingtonia' was coined in modern botanical (New Latin) usage by Latinizing the English proper name 'Washington' with the suffix '-ia', producing the genus name 'Washingtonia' used in scientific classification.

Initially it meant a Latinized name honoring 'Washington'; over time it has come to denote the specific genus of palm trees known as 'Washingtonia'.