John

John male forename.
John Barleycorn a personification of barley, or of the malt liquor made from this grain; the term is recorded from the early 17th century, in the title of a ballad of ‘the bloody murther of Sir John Barleycorn’.
John Bull a personification of England or the typical Englishman, represented as a stout red-faced farmer in a top hat and high boots. The name is that of a character representing the English nation in John Arbuthnot's satire Law is a Bottomless Pit; or, the History of John Bull (1712).
John Company a nickname for the East India Company, taken over from the name Jan Kompanie, by which the Dutch East India Company and Dutch government were traditionally known in the East Indies; a translation (1785) of Sparrman's Voyage to the Cape of Good Hope notes that the Dutch as traders in this area had represented their company as ‘one individual powerful prince, by the Christian name of Jan or John’, and that from this the writer had told his interpreter to say ‘that we were the children of Jan Company’.
John Hancock informal American expression for a personal signature, perhaps from the American Revolutionary leader John Hancock (1737–93), the first of the signatories to the Declaration of Independence.

See also Blue John at blue, Dear John letter.