Noah Webster's New International Dictionary of the English Language
1. (n.) The act of uniting or joining two or more things into one, or the state of being united or joined; junction; coalition; combination.
2. (n.) Agreement and conjunction of mind, spirit, will, affections, or the like; harmony; concord.
3. (n.) 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; as, the weavers have formed a union; trades unions have become very numerous; the United States of America are often called the Union.
4. (n.) A textile fabric composed of two or more materials, as cotton, silk, wool, etc., woven together.
5. (n.) A large, fine pearl.
6. (n.) A device emblematic of union, used on a national flag or ensign, sometimes, as in the military standard of Great Britain, covering the whole field; sometimes, as in the flag of the United States, and the English naval and marine flag, occupying the upper inner corner, the rest of the flag being called the fly. Also, a flag having such a device; especially, the flag of Great Britain.
7. (n.) A joint or other connection uniting parts of machinery, or the like, as the elastic pipe of a tender connecting it with the feed pipe of a locomotive engine; especially, a pipe fitting for connecting pipes, or pipes and fittings, in such a way as to facilitate disconnection.
8. (n.) A cask suspended on trunnions, in which fermentation is carried on.