The Collaborative International Dictionary of English v.0.48:

Scutage \Scu"tage\ (?; 48), n. [LL. scutagium, from L. scutum a
   shield.] (Eng. Hist.)
   Shield money; commutation of service for a sum of money. See
   Escuage.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tallage \Tal"lage\, Talliage \Tal"li*age\, n. [F. taillage. See
   Taille, and cf. Tailage.] (O. Eng. Law)
   A certain rate or tax paid by barons, knights, and inferior
   tenants, toward the public expenses. [Written also tailage,
   taillage.]
   [1913 Webster]

   Note: When paid out of knight's fees, it was called
         scutage; when by cities and burghs, tallage; when
         upon lands not held by military tenure, hidage.
         --Blackstone.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Escuage \Es"cu*age\ (?; 48), n. [OF. escuage, F. ['e]cuage, from
   OF. escu shield, F. ['e]cu. See Esquire.] (Feud. Law)
   Service of the shield, a species of knight service by which a
   tenant was bound to follow his lord to war, at his own
   charge. It was afterward exchanged for a pecuniary
   satisfaction. Called also scutage. --Blackstone.
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

SCUTAGE, old Eng. law. The name of a tax or contribution raised for the use
of the king's armies by those who held lands by knight's service.