Generally, when I write the Raga Review of a particular raga, I use the terms Jiva swara, Gruha Swara etc. Here is a small attempt to explain what are these terms.
1.Gruha Swaram is the note on which the Raga is commenced. There may be One, Two or even more Graha Swaras in a Ragam.
2.Hamsa/Jiva Swaram is the note which reveals the melodic identity of the Raga; (Soul of the raga).