A backyard is an area of land at the back of a house.
N-COUNT
（某国的）后院（指本土或该国意欲施加影响的邻近地区）
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.
例句
Economics will not stop Europe's politicians complaining when jobs are lost in their own backyard...当本国人口在失业时，经济情况是无法让欧洲的政治家停止抱怨的。Cuba is the largest island in the Caribbean, an area that the United States has long regarded as its own backyard.古巴是加勒比地区最大的岛屿，美国长期以来一直把它看作自己的后院。
英汉词典释义
n.
<美>(屋后有草皮的)后院;后花园
He stacked the firewood in the backyard.他把木柴堆在后院。The boys buried the dead bird in the backyard.孩子们把死鸟埋在后院。The defence party divided his backyard from that of his sister’s.一堵共用的墙把他跟他妹妹的后院隔开了。My house had a small backyard,the paradise of children.我那幢房子有一个小后院,那是孩子们玩耍的乐园。Our house is on an acre of land which gives us a nice big backyard for our garden.我们的房子坐落在一英亩的土地上,因而后院地方很大,可供我们辟为花园。The party leader is facing opposition in his own backyard .该党领袖在自己的党內遇到了反对。
<美>被看作自家后院一般的地方;邻近地区
Come on, I’ll give you the grand tour of the backyard.跟我来，我带你去后院来一次盛大的旅游。The residents didn’t want a new factory in their backyard.居民不希望在他们住地附近建新工厂。
在自己的后院；离自己的住所(或工作场所)很近的地方
The residents didn’t want a new factory in their backyard.居民不希望在他们住地附近建新工厂。The party leader is facing opposition in his own backyard.该党领袖在自己的党内遇到了反对。