Question

look at this sentence:

the american federation of teachers is a trade union that represents individuals in education, health care, and public service.

select the definition of union that the sentence uses.

union \yoon-yuhn\\ noun pl unions 1. a bond that results from joining two or more things: marriage is a union that strengthens society. 2. an organization of workers joined to protect their rights and interests: the union decided to strike after salary negotiations failed. 3. a group of states or nations joined into a larger political body: after world war ii, several european countries began working to form a union. 4. a device for connecting parts of a machine: i’m missing the union that joins the two water pipes together. — from latin

Explanation:

The sentence says the American Federation of Teachers is a trade union representing individuals in education, health care, and public service. A trade union is an organization of workers (teachers here) to protect their rights/interests, which matches definition 2. Other definitions don't fit: 1 is about a bond of things, 3 about states/nations, 4 about a machine part.

Answer:

1. an organization of workers joined to protect their rights and interests: The union decided to strike after salary negotiations failed.