1.
(also by courtesy of sb/sth ) with the official permission of sb/sth and as a favour :
The pictures have been reproduced by courtesy of the British Museum.
2.
given as a prize or provided free by a person or an organization :
Win a weekend in Rome, courtesy of Fiat.
3.
as the result of a particular thing or situation :
Viewers can see the stadium from the air, courtesy of a camera fastened to the plane.