Abhidhana

Abhidhana is a Sanskrit word which refers to any Sanskrit dictionary or vocabulary. There are many Abhidhanas. One of them, which is considred to be the oldest is Abhidhana-Ratnamia of Halayudha Bhatta ( that dates to circa seventh century). One more example of Abhidhana is Abhidhana Chintamani of Hemachandra, a Jaina writer of 11th and 12th century.