Labor relations is a broad field encompassing all the myriad interchanges between employers and employees. While the term is most often used to discuss this exchange as it pertains to unionized employees, it may also refer to non-union employees as well.
What are Labor Relations (Webpage)
About 14 million U.S. workers belong to unions—around 11.3% of the total number of men and women working in this country.
Labor unions have a long and colorful history in the United States. To some people, they conjure up thoughts of organized crime and gangsters like Jimmy Hoffa. To others, labor unions represent solidarity among the working classes, bringing people together across many professions to lobby for better rights, wages and benefits.
How Labor Unions Work (Webpage)