1. 成员组织；附属机构；分会
    An affiliate is an organization which is officially connected with another, larger organization or is a member of it.

    e.g. ...twelve companies, including three affiliates of a Texas oil firm...
           12家公司，包括得克萨斯一家石油公司的3家分公司
    e.g. The World Chess Federation has affiliates in around 120 countries.
           国际象棋联合会在大约120个国家设有分支机构。

2. 隶属于;并入
    If an organization affiliates to or with another larger organization, it forms a close connection with the larger organization or becomes a member of it.

    e.g. All youth groups will have to affiliate to the National Youth Agency...
           所有青年团体必须并入全国青年事务处。
    e.g. The Government will not allow the staff association to affiliate with outside unions.
           政府不会允许其公务员协会与外部工会有紧密联系。

3. （医生或律师等专业人士）与…有正式关系
    If a professional person such as a lawyer or doctor affiliates with an organization, they become officially connected with that organization.

affiliate的近义词

    e.g. He said he wanted to affiliate with a U.S. firm because he needed 'expert advice and counsel in legal affairs'.
           他说他因为需要“在法律事务上得到专家的意见和建议”，所以想与一家美国律师事务所建立合作关系。