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.
Definition of 'index'. index (Éªndeks ) Word forms: plural indices , plural , 3rd person singular present tense indexes , present participle indexing , past tense , past participle indexed language note: The usual plural is indexes, but the form indices can be used for meaning [sense 1].