Final answer:
The term 'Achilles heel' refers to someone's vulnerable point. In Greek mythology, Achilles had a weakness in his heel, which led to his downfall. The term is now used figuratively to describe someone's weakness or vulnerable point.
Step-by-step explanation:
The term 'Achilles heel' refers to someone's vulnerable point. In Greek mythology, Achilles was a legendary hero who was invincible except for his heel, which his mother held onto when dipping him in the river Styx. This vulnerable spot ultimately led to his downfall when he was struck by an arrow there. The term is now used figuratively to describe someone's weakness or vulnerable point.