means A tough, fibrous band of tissue that connects muscle to bone, transmitting the force of contraction so the bone actually moves.

from From Latin 'tendo, tendinis,' itself tied to 'tendere,' to stretch or strain — the same straining root behind 'tension' and 'tend.' Medieval Latin anatomists likely shaped it under the influence of Greek 'tenon' (sinew), a cousin from the same Indo-European stretching family. So a tendon is, quite literally, the body's stretched thing.