From WordNet (r) 3.0 (2006) [wn]:
countryside
n 1: rural regions
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Countryside \Coun"try*side`\ (-s?d`), n.
A particular rural district; a country neighborhood. [Eng.]
--W. Black. Blackmore.
[1913 Webster]