Hamstring n. : One of the great tendons situated in each side of the ham, or space back of the knee, and connected with the muscles of the back of the thigh.

Hamstring v. t. : To lame or disable by cutting the tendons of the ham or knee; to hough; hence, to cripple; to incapacitate; to disable.

Example:
How can I train my Hamstring and my calfs muscles? What is the most important part of my arm for running?

Taxonomy
hamstring, knee, tendons, muscles, biceps femoris, layer, hip extension, Hamstring injuries, free encyclopedia, origin, thigh muscles, Injury, semitendinosus, semimembranosus, short head, cross, trunk, quadriceps.

Defination from the web:
hamstring refers to one of the three posterior thigh muscles, or to the tendons that make up the borders of the space behind the knee. ... In strength training, the hamstrings are trained in isolation with the leg curl exercise, as well as a part of several other ...