Lit. 'nobility of the court'. Before the 14c those who surrounded the king were of the nobility, whose position and power were somewhat independent of the crown. In many ways they were his companions. However, as the court and its attendant administrative functions increased, laymen or clerks were required for specialist roles, and the most important of these officials were ennobled. The distinction also carried the implication that their rank was not conferred on the battlefield.
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.