1. an
instrument,
agent, via,
channel, person, etc., used to convey some
communication,
particle,
action, etc., from a
point of
origin to a
point of
receipt.
2. a means of communicating or presenting a
message to the
broad public such as newspapers,
magazines, radio, television, mail, billboards, etc., used to advertise, inform, or appeal to the
public.