noun
: an involuntary forward jerk or kick induced by a light blow or sudden strain upon the patellar tendon of the knee that causes a reflex contraction of the quadriceps muscle
noun
: an involuntary forward jerk or kick induced by a light blow or sudden strain upon the patellar tendon of the knee that causes a reflex contraction of the quadriceps muscle
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012