Hystera = womb or uterus
Hysterikos = a suffering in the womb
Plato and his followers described the uterus as an animal endowed with spontaneous sensation and motion, lodged in a woman, and ardently desiring to bear children. If it remained sterile long after puberty, it became indignant, dissatisfied, and ill-tempered and caused a general disturbance of the body until it became pregnant, when it became normal again.
This is in keeping with the age-old proclivity to attribute various abnormal manifestations to specific organs of the body. Emotional instability, thought to be more characteristic of women than men, was atttributed to the uterus."