भूवादयो धातवः

This defines the word dhatu or root. The list of Sanskrit verbs begins with the root bhu 'to be.' Sanskrit grammarians have divided all verbs into ten classes, according to certain modifications which their roots undergo before certain terminations. The ten classes are as follows:-

1. Bhu class. 2. Ad. 3. Hu. 4. Div. 5. Su, 6. Tud. 7. Rudh. 8. Tan. 9. Kri. 10. Chur.

There are about two thousand verbs, and they are conjugated in two forms, some taking the Parasmaipada terminations only, the others the Atmanepada terminations and some both. The present chapter deals mostly with rules determining the nature of the verbal root, whether it is Parasmaipadi or Atmanepadi or both. A verb expresses action. The word dhatu is a word coined by older grammarians than Panini and they employed the term in denoting a word expressing action. Here also, therefore, the word dhatu means a word which expresses action.

The वा in the sutra is for the sake of auspiciousness; for the regular sandhi of भू + आदि is भ्वादि and not भूवादि; while Dr. Ballantyne considers that वा is a separate root : he translates the sutra thus:- \Let the verbal roots bhu 'be,' va 'blow' and the like be called dhatu.\,