Lit. 'the king's land'. Phrase used in *DB for all the land still in the king's possession, i.e. that which had not been given to one of his barons or other person in return for services. The term continued in use well into the 12c, when there was still much land held by the king himself. Such land was known as the 'royal *demesne'. However, this was not a static portfolio.
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.