The history of Sanskrit dictionary is, perhaps, older than that of the Sanskrit Grammar. It got started with Vedic Concordance named ‘Nighantu’. In reality, instead of being a dictionary, Nighantu is more or less a word. During later period, various dictionaries were compiled but, unfortunately, we have lost their original scripts.
Amara Simha’s ‘Amarakosa’ has been considered to be the oldest and most popular compilation. It is also known as Namalinganusasana. in later period, Halayudha-kosa, Vaijayanti-kosa, Mankha-kosa, Nama-mala and Anekartha-samgraha etc. names are worth mentioning.