breeding ground
noun [ C ] uk/ˈbriː.dɪŋ ˌɡraʊnd/ us/ˈbriː.dɪŋ ˌɡraʊnd/
（动物的）繁殖地
a place where animals breed and produce their babies
These animals always return to the same breeding ground. 这些动物总是回到同一个地方繁殖。
（尤指坏事的）滋生地
a place where something develops easily, especially something unpleasant
Poor housing conditions are breeding grounds for crime. 糟糕的居住环境滋生犯罪。