union

club, association, institute, league, union, society

这些名词均有“社团，会社，协会”之意。
club: 表俱乐部或会社，其成员因志同道合，有共同兴趣、爱好而组织到一起进行社交、娱乐或体育等活动。
association: 指较为正式的组织，强调兴趣和需要的一致性。
institute: 指为专门的目标而建立的学会或研究所。
league: 指为了共同的目的和利益而组成的社团、同盟或联合会。
union: 多指工会，也指学会或协会。
society: 可与association换用，但前者的宗旨更严格，会员之间联系更紧密，活动更积极。

league, federation, union, alliance

这些名词均含“联盟、同盟、联合会”之意。
league: 普通用词，指为了共同的利益而建立的地区性、全国性或国际性的联合组织，也指民间或半官方组织的联盟。
federation: 泛指用条款固定下来的一切联合，尤指联邦政府。
union: 普通用词，指由若干个体结成的一个统一的整体。强调其永久性。
alliance: 普通用词，指对双方均有利的任何联盟。

名词 union:

1. an organization of employees formed to bargain with the employer
   同义词：labor union, trade union, trades union, brotherhood
2. the United States (especially the northern states during the American Civil War)
   同义词：North
3. the act of pairing a male and female for reproductive purposes
   同义词：coupling, mating, pairing, conjugation, sexual union
4. the state of being joined or united or linked
   同义词：unification
5. the state of being a married couple voluntarily joined for life (or until divorce)
   同义词：marriage, matrimony, spousal relationship, wedlock
6. healing process involving the growing together of the edges of a wound or the growing together of broken bones
   同义词：conglutination
7. a political unit formed from previously independent people or organizations
8. a set containing all and only the members of two or more given sets
   同义词：sum, join
9. the occurrence of a uniting of separate parts
10. a device on a national flag emblematic of the union of two or more sovereignties (typically in the upper inner corner)
11. the act of making or becoming a single unit
    同义词：unification, uniting, conjugation, jointure

形容词 union:

1. being of or having to do with the northern United States and those loyal to the Union during the American Civil War
   同义词：Federal
2. of trade unions

1. The Trade Union Movement works to obtain higher wages and better conditions.
   工会运动旨在争取更高的工资和更好的工作条件。
2. Fifteen separate republics comprised the Soviet Union.
   苏联由十五个加盟共和国组成。
3. The union struck for better work conditions.
   工会为争取更好的工作条件而罢工。
4. We all accused the union of torpedoing the negotiation.
   我们都谴责工会破坏谈判。
5. He was elected the leader of the union.
   他被选为工会的领导人。
6. The group have split away/off from the official union.
   这一部分人已从正式的联盟中分裂出来了。
7. The artist's work shows the perfect union of craftsmanship and imagination.
   这位艺术家的作品表现了技艺和想象力的完美的结合。
8. Do you belong to a union?
   你属于某个工会吗？