As if the oceans needed more terrible news, scientists have learned that the coral reefs surrounding the Florida Keys are dissolving. The culpritâocean acidificationâwasnât expected to start hitting reefs hard for another three decades.
index noun (LIST) C1 [ C ] an alphabetical list, such as one printed at the back of a book showing which page a subject, name, etc. is on: Try looking up heart disease in the index. âº [ C ] a collection of information stored on a computer or on a set of cards, in alphabetical order:
Dictionary entry overview: What does index fossil mean? â¢ INDEX FOSSIL (noun) The noun INDEX FOSSIL has 1 sense: 1. a fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found Familiarity information: INDEX FOSSIL used as a noun is very rare.