A Climacteric

1. A critical stage or decisive point; a turning point. [from 17th c.]
2. A period in human life in which some great change is supposed to take place, calculated in different ways by different authorities (often identified as every seventh or ninth year). [from 17th c.]
3. (medicine) The period of life that leads up to and follows the end of menstruation in women; the menopause. [from 18th c.]