Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
index [ˈɪndɛks] (pl indexes) n (in book) (слова́рь*)указа́тель m (in library etc) катало́г; (pl indices) (MATH) показа́тель*msg
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: