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.
The normal rhythm of breathing is called [46], whereas difficulty in breathing and shortness of breath is called [47]. A temporary cessation of breathing is [48] and a permanent cessation (unless there is successful intervention) is [49]. Abnormally rapid breathing, which expels CO2 faster than the body produces it, is called [50] and is frequently due to anxiety attacks.