Definition of courier
1
: messenger: such as
a
: a member of a diplomatic (see diplomatic 2) service entrusted with bearing messages
b (1)
: an espionage agent transferring secret information
(2)
: a runner of contraband (see contraband 2)
- drug couriers
c
: a member of the armed services whose duties include carrying mail, information, or supplies
2
: a traveler's paid attendant;
especially
: a tourists' guide employed by a travel agency
