symbiosis
noun [ U ] uk/ˌsɪm.baɪˈəʊ.sɪs/ us/ˌsɪm.baɪˈoʊ.sɪs/
biology specialized（动物或植物间的）共生
a relationship between two types of animal or plant in which each provides for the other the conditions necessary for its continued existence
（人或机构间的）相互依赖的关系，互依关系
a relationship between people or organizations that depend on each other equally