Marshalsea \Mar"shal*sea\, n. [Marshal + OE. se a seat. See {See} a seat.] The court or seat of a marshal; hence, the prison in Southwark, belonging to the marshal of the king's household. [Eng.] {Court of Marshalsea}, a court formerly held before the steward and marshal of the king's house to administer justice between the king's domestic servants. --Blackstone.