tendon

Tendon comes from French tendon or Medieval Latin tendō, which trace back to Ancient Greek τένων (ténōn, "sinew, tendon"). Its form was reshaped by association with the Latin verb tendō, meaning "to stretch."

The word entered English through French and Medieval Latin, carrying its anatomical meaning of a stretched, cord-like tissue connecting muscle to bone; Middle English had its own version, thenoun, before the modern spelling settled in.

It shares a root idea with the Latin verb tendō, "to stretch," which also gives English words like 'tension' and 'extend' — all built on the notion of pulling taut. (Note: a separate word, 'tendon' in Japanese cooking, meaning a tempura rice bowl, is unrelated — it's a clipping of tenpura donburi.)