Term: Achilles tendon or Achilles’ tendon
Origin: Anc Greek
Aχιλλέας/Achilleas(=Achilles, a Greek hero of the Trojan War).
According Greek mythology Achilles was the the son of the the Nereid Thetis, a sea-goddess, possessing a semi-divine birth. His mother dipped him as a baby into waters of the River Styx in order to make him immortal but since his left ankle remained covered by her hands, that part of him remained mortal. Finally Achilles was died from a heel wound which he receives from a goddess-guided arrow shot by Paris (Πάρις) of
τένοντας/tenontas(=tendon) > τεντώνω/tentono(=strain)
The Achilles tendon, is a tough sinew of the posterior leg that serves to attach the calf muscle to the back of the heel bone.