What is Baron?

Legal Definition
This word has but one signification in American law, namely, husband: we use baron and feme, for husband and wife. And in this sense it is going out of use.

2. In England, and perhaps some other countries, baron is a title of honor; it is the first degree of nobility below a viscount. Vide Com. Dig. Baron and Feme; Bac. Ab. Baron and Feme; and the articles. Husband; Marriage; Wife.

3. In the laws of the middle ages, baron or bers, (baro) signifes a great vassal; lord of a fief and tenant immediately from the king: and the words baronage, barnage and berner, signify collectively the vassals composing the court of the king; as Le roi et son barnage, The king and his court. See Spelman's Glossary, verb. Baro.
-- Bouviers Law Dictionary
Legal Definition
A lord or nobleman; the most general title of nobllity in England. 1 BL Comm. 398, 399. A particular degree or title of nobility, next to a viscount. A judge of the court of exchequer. 3 BL Comm. 44; Cowell. A freeman. Co. Litt 58a. Also a vassal holding directly from the king. A husband; occurring in this sense in the phrase "baron et feme," husband and wife,
See also
-- Black's Law Dictionary
Legal Definition
Baron is a title of honour, often hereditary. The female equivalent is baroness.
-- Wikipedia
Legal Definition
A judge or officer of the court of exchequer; a husband; a vassal of the king.
-- Ballentine's Law Dictionary