அது - Adhu
pron. (pl. அவை, அவைகள், அவற்று) that, it, that thing; 2. termination of the sixth or possessive case as அவனது கை.
அதது, each. அதற்கப்புறம், beyond that, further. அதுக்குள், அதற்குள், within that thing, within that time, in the mean time. அதுக்கென்ன, அதற்கென்ன, what of that? what does it signify?. அதுவே, that very thing, the same; அவற்றின் தன்மை, their nature and qualities.