The difference between Guild and Union

Guild as a noun:

A group or association mainly of tradespeople made up of merchants, craftspeople, or artisans for mutual aid, particularly in the Middle Ages.

Guild as a noun:

A corporation.

Guild as a noun (ecology):

A group of diverse species that share common characteristics or habits.

Guild as a noun (video games):

An organized group of players who regularly play together in a multiplayer game.

Union as a noun (countable):

The act of uniting or joining two or more things into one.

Union as a noun (uncountable):

The state of being united or joined.

Union as a noun (countable):

That which is united, or made one; something formed by a combination or coalition of parts or members; a confederation; a consolidated body; a league.

Union as a noun (countable):

A trade union; a workers' union.

Union as a noun (countable):

An association of students at a university for social and/or political purposes; also in some cases a debating body.

Union as a noun (countable):

A joint or other connection uniting parts of machinery, such as pipes.

Union as a noun (countable, set theory):

The set containing all of the elements of two or more sets.

Union as a noun (countable):

The act or state of marriage.

Union as a noun (uncountable, archaic, euphemistic):

Sexual intercourse.

Union as a noun (countable, programming):

A data structure that can store any of various types of item, but only one at a time.

Union as a noun (countable, now, _, rare, archaic):

A large, high-quality pearl.

Union as a noun (historical):

An affiliation of several parishes for joint support and management of their poor; also the jointly-owned workhouse.

Union as a verb:

To combine sets using the union operation.