Freebase(0.00 / 0 votes)Rate this definition: Portable Network Graphics. Portable Network Graphics is a raster graphics file format that supports lossless data compression. PNG was created as an improved, non-patented replacement for Graphics Interchange Format, and is the most used lossless image compression format on the World Wide Web.
Definition of menopause. 1 : the natural cessation of menstruation that usually occurs between the ages of 45 and 55; also : the period during which such cessation occurs âcalled also climacteric â compare perimenopause. 2 : cessation of menstruation from other than natural causes.
Menstruation (Definition). Menstruation is also known as Menses. Menstruation is the regular cyclical shedding of uterine (womb) lining associated with bleeding. Begins at puberty (menarche) and continus during a woman's fertile years until menopause. Cycles usually average 28 days, but can vary from 21 - 35 days.