Achilles' tendon is a commonly used term that refers to the thick fibrous band that connects the calf muscles to the heel bone. However, there are several synonyms or alternate names for the Achilles' tendon. Some of these synonyms include calcaneal tendon, heel cord, tendo calcaneus, or tendo Achilles. Medical professionals and sports enthusiasts may use one of these alternate terms while referring to the same tendon. Whatever the name, the Achilles' tendon is a vital structure that allows us to walk, jump, run, and perform other daily activities. It is susceptible to injury, so it's important to take care of it.