Main Entry: in·dex

Pronunciation: \ˈin-ˌdeks\

Function: noun

Inflected Form(s): plural in·dex·es or in·di·ces \-də-ˌsēz\

1 : index finger
2 : a list (as of bibliographical information or citations to a body of literature) arranged usually in alphabetical order of some specified datum (as author, subject, or keyword) <Index Medicus of the United States National Library of Medicine>
3 a : a ratio or other number derived from a series of observations and used as an indicator or measure (as of a condition, property, or phenomenon) <physiochemical indexes of the urine, the blood, and the gastric juice—Journal of the American Medical Association> b : the ratio of one dimension of a thing (as an anatomical structure) to another dimension—see cephalic index, cranial index