The word Menopause literally means the physiological cessation of menstrual cycles, from the Greek roots 'meno-' (month) and 'pauses' (a pause, a cessation). However, in reality menopause is not simply a matter of the permanent stopping of periods, it is a phenomenon which involves the shutting down of the whole of a woman's reproductive functioning.

The root cause of menopause is not what is happening to the uterus, the whole process of menopause is triggered by the faltering and shutting down of the ovaries. This process usually normally occurs more or less in midlife.
Clinically speaking, menopause is referred to with a date: the date of the day after a woman's last period ever finishes.

The normal age range for last period ever is between age 45 to 55, with the peak being at about age 51. An "early menopause" is defined as last period ever at an age between 40 to 45. Age 55 to 60 for last period ever is described as a "late menopause". Last period ever prior to age 40 is considered a "premature menopause", and this is not viewed as being due to normal causes.

In common everyday parlance however, the word "menopause" is most often used to refer to the menopause transition years, also known as the change of life or the climacteric. This time of life is also sometimes known as perimenopause, (literally meaning around menopause).

Image Source: www.nlm.nih.gov