(biblical) Persons of the Christian Bible: John the Baptist; and names possibly referring to one, two or three persons, frequently called "Saint": John the Apostle, John the Evangelist and John of Patmos (also called John the Divine or John the Theologian).

(biblical) The Gospel of St. John, a book of the New Testament of the Bible. Traditionally the fourth of the four gospels.

(biblical) One of the books in the New Testament of the Bible, the epistles of John (1 John, 2 John and 3 John).

(UK, military, slang) A new recruit at Royal Military Academy Sandhurst.

(slang) A prostitute's client.

(slang, US) A device or place to urinate and defecate: now usually a toilet or lavatory, but also a chamber pot or outhouse.

(slang) A Western man traveling in East Asia.

A male mule.