Kathirvel Pillai of Sri Lanka is the author of Tamil sol-l-akarati (Dictionary of Tamil Words) published in 1904. It is one of the most important modern dictionaries of Tamil. Archaic dictionaries of earlier times were all couched in verse-form, intended for memorization and arranged according to subjects – not of much use to modern students.
A deep study, coupled with total, enabled Kathirvel Pillai to collect about 64,000 Tamil words, which he presented alphabetically in three sumptuous volumes, each entry having numbered meanings of the words, often with etymologies, derivations, and quotations from sources.
In the matter of the full elucidation of the word, the author himself observes, most prominently – I have included in the present work the words derived and gradually adopted from Sanskrit to modern requirements, and now appropriated by writers as part and parcel of the Tamil language. To those wishing to study Vedanta and Shaiva Siddhanta, the dictionary will be of great help. Medical men will be glad to find botanical and medical words. Technical words relating to Logic, Rhetorics, Astrology, Astronomy, and Mathematics have received special attention. Works of Sanskrit origin are traced to their sources and the originals from which they are derived are also given in Sanskrit characters (preface , p.viii).
Besides being a master lexicographer, Kathirvel Pillai was also a scholar in the philosophy of Saiva Siddhanta, in which he authored several books, all in Tamil, including Shivabushana Chandrika, Saiva Siddhanta Curukkam, and Shivakshetralaya Mahotsava Unmai Vilakkam.
For the benefit of non-Sanskrit knowing scholars, he wrote commentaries in Tamil on the Sanskrit Kurma Puranam, Shivaratri Puranam and Naisadhiya Caritam. Three other books that he wrote are Pattinathar Puranam, Arunai-K-Kalampakam and Subrahmanya Parakramam.
Besides being an all-round scholar, Katirvel Pillai had a phenomenal memory and could perform feats such as answering multiple questions put to him at one time.