Of English origin, the term index refers to an indication or a sign of something. Synonym index, it can be of the numeric expression of the relationship between two quantities, sizes or different types of indicators. Examples: "the Government does not meet the new economic indices", 'In demographic terms, there is strong evidence indicating that the village will eventually empty in the next five years, that the population fears', 'tickets exhausted in all theatre rooms are the best indicator of recovery of consumption.
In a publication or a book, the index is a list northing (generally in alphabetical order) chapters, of authors of materials, articles, key words, etc. The index allows the reader to know what are the content included in the book and where to locate them through references to find them. It is usually at the beginning or at the end of the book: "Look in the index which page is the interview with the Swiss author", 'drawback of this novel, is that there is no index', "according to the index, the final chapter starts on page 84.
The index is also the catalogue of what contains one archive or library: ' let me see in the index if we have this book in our shelves ","If you want to know where to find the material you need, please consult the index. "
In computing, the index is a fixed value that allows complete (or correct, if necessary) the values of some addresses executing a statement, and that is precisely maintained in the registry of the computer index.