Floridaâs tract of coral reefs has the honor of being the third-largest barrier reef ecosystem in the world. However, it could soon be a thing of the past, as the acidification of the oceanâs water is dissolving it faster than it can rebuild.
index (plural indexes or indices) 1  An alphabetical listing of items and their location. The index of a book lists words or expressions and the pages of the book upon which they are to be found. 2  The index finger; the forefinger. 3  A movable finger on a gauge, scale, etc.
Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2). The WHO definition is: 1  a BMI greater than or equal to 25 is overweight.