From Longman Dictionary of Contemporary EnglishAchilles tendonA·chil·les ten‧don /əˌkɪliːz ˈtendən/ noun [countable] HBHthe part of your body that connects the muscles in the back of your foot with the muscles of your lower leg
Examples from the Corpus
Achilles tendon• Charles has struggled with knee trouble while Wilson has been plagued by Achilles tendon and hamstring problems.• The scrum-half arrived from New Zealand and promptly injured his Achilles tendon.• The bike fell on him, tearing his Achilles tendon, which is no joke at all.• He walked with a lilting gait, his left Achilles tendon apparently shortened, pulling his left heel up.• It is slightly cut away at the rear and so doesn't put pressure on the Achilles tendon.• It consisted of stretching the Achilles tendon. 