A backyard is an area of land at the back of a house.
2.?[C 可数名词] （国家的）后院
If you refer to a country's own backyard, you are referring to its own territory or to somewhere that is very close and where that country wants to influence events.
双语例句
例：
They seem to think that if it isn't happening in their own backyard, it isn't worth worrying about.