'assemblywoman' originates from Modern English, specifically a compound of 'assembly' and 'woman', where 'assembly' meant 'a meeting of people' and 'woman' meant 'an adult female'.

'assemblywoman' was formed in Modern English by compounding the noun 'assembly' (a meeting or legislative body) with 'woman' to denote a female member of an assembly; the formation reflects 19th–20th century patterns of creating gender-specific office titles.

Initially it could simply refer to a woman who attended or belonged to an assembly; over time it came to be used specifically for a female member of a legislative assembly.