The fourth of the four இலக்கண வகை types: a உரிச்சொல் is a word that belongs specially to one meaning (or one meaning to it) - it splits into 2 functional kinds by that relationship.

Several words all pointing to excess, yet none of them a noun, verb, or particle - உரிச்சொல் is Tamil grammar's answer to what to call them.

சால, உறு, தவ, நனி - all meaning "excess", each a உரிச்சொல்.