A more thorough explanation:

Definition: Scutage (skyoo-tij) is a historical term that refers to a monetary payment made by barons to the king in lieu of providing knights for military service. The term comes from the Latin word "scutum," which means "shield."

Scutage was first introduced in the 12th century by King Henry II, who levied five scutages in the first 11 years of his reign. The payment was made by barons who were required to provide knights for military service to the king. Instead of providing knights, they could pay a fee to the king, which was known as scutage.

Scutage was also used as a fee paid by a tenant-in-chief by knight-service in lieu of serving in a war. It was a tax on a knight's estate to help furnish the army. The payment of scutage was most highly developed in England, where it became a general tax on knights' estates at rates that were standardized by the thirteenth century.

For example, if a baron was required to provide ten knights for military service, but he only provided five, he could pay scutage for the remaining five knights. Similarly, if a tenant-in-chief was required to serve in a war but could not do so, he could pay scutage instead.

Scutage became obsolete by the fourteenth century, but it played an important role in medieval feudal law and the development of taxation in England.