In music scale (shruti) there can be 12 kind of sounds that match the scale (shruti). These types of sound in music are called swar or note. In music there are 12 swaras (notes). Out of those 12 swaras 7 swaras are shudha(pure), 4 swaras are komal and 1 swar is tivra.
Shudhha, Achal, Komal, and Teevra Swar
Achala Swar : The notes Shadja and Pancham are fixed on the scale. They are referred to as Achal swara (immovable).
Vikrut Swar : The other notes viz. Rishabh, Gandhar, Madhyam, Dhaivat and Nishad are Vikrut (Movable).
Komal Swar : In Vikrut swaras Rishabh, Gandhar, Dhaivat, Nishad can be moved below there shuddha place on the scale. They are called komal (Soft or Flat). These are shown by a small horizontal line below the note.
Teevra Swar : Only Madhyam, can become vikrut by going one note above the shuddha Madhyam. It is called teevra (Sharp). It is shown by a small vertical line above the note.
Shadja – Sa
Rishabh – Re
Gandhar – Ga
Madhyam – Ma
Pancham – Pa
Dhaivat – Dha
Nishad – Ni