Latin baro originally simply 'man' and a synonym of homo, but later used specifically of a king's man, and hence later of a baron.
Cite as: J. Uckelman, S.L. Uckelman. "Baron". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2016, no. 4. http://dmnes.org/2016/4/name/Baron.