郊区 (jiāoqū) is a noun meaning "suburb" or "outskirts." It refers to the residential or less urbanized areas on the edge of a city, and is used when distinguishing between the city center and surrounding areas.
他们在郊区买了一套带院子的房子。
tāmen zài jiāoqū mǎi le yī tào dài yuànzi de fángzi.
They bought a house with a yard in the suburbs.
这座城市的郊区发展得越来越快了。
zhè zuò chéngshì de jiāoqū fāzhǎn de yuèláiyuè kuài le.
The suburbs of this city are developing faster and faster.
每到周末,很多人开车去郊区露营。
měi dào zhōumò, hěn duō rén kāichē qù jiāoqū lùyíng.
Every weekend, many people drive to the suburbs to go camping.