Pain in the region of the Achilles tendon, the thick tendon at the back of the heel that connects the calf muscle to the heel bone.
From Achilles (the heel tendon) plus -odynia (from Greek odyne, meaning pain). It's a medical term combining Greek elements following standard medical naming conventions.
Achillodynia is what runners and weekend athletes dread—the Achilles tendon can only stretch so much before damage occurs, and once it starts hurting, it's notoriously difficult to heal because tendons get relatively little blood flow.
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