German soldiers hired by the British were called Hessians.
"Hessians" was the name given for German troops coming from the German states of Hesse-Kassel and Hesse-Hanau (from where the name "Hessians" is derived) and other small states, that were fighting for the British. Even though they were hired to fight in several 18th-century European wars, they are most widely known for fighting in the American Revolution War (1775–1783), in which around 30.000 German soldiers participated.