Parent scale, parent mode; Thaat means to tie down as in frets
10 different sets of musical scales with seven primary notes in order of ascent and in sequence only to help categorise the maximum number of Hindustani ragas under it.
A scale or mould out of which a group of ragas originate
A thaat is a musical mode in Hindustani music which always has seven notes (excluding the repeated tonic) and is mainly used for the classification of ragas in a system created by Pt. Vishnu Narayan Bhatkhande. A thaat is a specific set of swara.