Jaati is a tonal classification of a Raag based on the number of notes employed in its Ascending & Descending scale.
e.g. Pentatonic Scale - 5 notes = Audhav Jaati
Hexatonic Scale - 6 notes = Shadhav Jaati
Septatonic Scale - 7 notes = Sampoorna Jaati.
Thus there are 9 Jaatis based on the combinations of the number of notes in aaroh and avroh:
Obviously there are notes in raagas from S. No 3 onwards in Aaroh or Avroh that are not employed in whole Raag.
It is possible that a note not employed in Aaroh may be used in Avroh and vice-versa.
In some cases, the rendering becomes Vakra (with a turn around that note). This is indicated in Jaati. e.g. Audhav-Sampoorna Vakra and so on.