Bachelor,
a term applied anciently to a person in the first or probationary stage of knighthood who had not yet raised his standard in the field. It also denotes a person who has taken the first decree in the liberal arts and sciences, or in divinity, law, or medicine, at a college or university; or a man of any age who has not been married. A knight bachelor is one who has been raised to the dignity of a knight without being made a member of any of the orders of chivalry such as the Garter or the Thistle.
Entry from Everybody's Cyclopedia, 1912.