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.
more dictionary definitions. 1  1. an alphabetical list of something such as subjects or names at the back of a book, that shows on which page they are mentioned Look up the term you want in the index. 2  2. economics a number that shows the price, value, or level of something compared with something else a wage/price index.