'usher' originates from Old French (Anglo-Norman) 'ussier', ultimately from Late Latin 'ostiarius', where 'ostium' meant 'door'.

'usher' changed from Anglo-Norman/Old French 'ussier' (a doorkeeper) and derived from Late Latin 'ostiarius'; it entered Middle English and became the modern English word 'usher'.

Initially, it meant 'doorkeeper' or 'one who watches/guards a door', and over time it came to mean more generally 'one who shows people to their seats' and the verb sense 'to lead or to introduce/bring in'.