Nighantu

Nighaṇṭu (Sanskrit:निघण्टु, IPA: [niɡʱəɳʈu]) is a Sanskrit term for a traditional collection of words, grouped into thematic categories, often with brief annotations. Such collections share characteristics with glossaries and thesauri, but are not true lexicons, such as the kośa of Sanskrit literature. Particular collections are also called nighaṇṭava.