a messenger, usually traveling in haste, bearing urgent news, important reports or packages, diplomatic messages, etc.

any means of carrying news, messages, etc., regularly.

the conveyance used by a courier, as an airplane or ship.

Chiefly British . a tour guide for a travel agency.

noun

receiver , sender

noun

bearer , carrier , dispatcher , emissary , envoy , express , go-between , gofer * , gopher , herald , intelligencer , internuncio , runner , conveyer , messenger , transporter , attendant , estafet , gofer , guide , mailman , post , postman , scout , spy