(, ) 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 .
While a number of nighantavas devoted to specialized subjects exist, the eponymous Nighantu of the genre is an ancient collection, handed down from Vedic times. It was the subject of the Nirukta, a commentary, together with a treatise on etymology, by Yaska. Technically, Yaska's Nirukta should designate his commentary only, but traditionally the Nighantu has been understood to be included in it.
n. (alternative spelling of Nighantu English)