A few basic terms used in Hindustani Classical Music are:
Aakar: It is the vocal improvisation using the long vowel ‘a’.
Alaap: The slow methodical progression of notes in a raga is called the Alaap.
Alankar (Palta):The specific melodic presentation in succession is the Alankar or Palta. Usually a pattern is followed in the Alankar.
Antara: The second stanza of a composition in a raga is the Antara. Usually an Antara is sung in the Madhya Saptak (medium octave region) or the Tar Saptak (higher octave region) of a raga.
Aroha and Avaroha:They are descriptions of how a raga moves.
Aroha (Anulom) is the upward movement or ascending order of notes in a raga ie movement from lower to higher notes. Eg The Aroha of Raga Durga is Sa Re Ma Pa Dha Ṡa Avaroha(Vilom/Bilom) is the downward movement or descending order of notes in a raga ie movement from higher to lower notes. Eg The Avaroha of Raga Durga is Ṡa Dha Pa Ma Re Sa
Dugun: When a unit is multiplied by two it is called a Dugun. The word Du means two and Gun means multiply.
Jaati of ragas: The class of a raga is its Jaati. A five-note raga is said to be an Audav Jaati; a six note raga is said to be Shadav Jaati and Sampoorna Jaati has seven notes. By combining any of the above 3 in a raga in its aroha and avroha, compound jaatis can be formed. Eg. Raga Jogia has 6 notes in its aroha and 7 notes in its avaroha and therefore is a Audav-Shadav Jaati raga.
Lakshan Geet : A composition where all the important features of a raga like swar, jaati, vadi-samvadi, suitable time to sing ,are sung like a poem is the Lakshan Geet of that raga.
Laya: The speed or tempo at which the rhythm is played is called the Laya. Laya can be Vilambit (slow), Madhya (medium), Drut (fast), Ati Vilambit (very slow) or Ati Drut (very fast).
Meend: The graceful gliding from one note to another note is called the Meend. Meend can be ascending or descending.
Pakad: The most minimal musical phrase used to describe a raga is called the Pakad. We can identify a raga by the Pakad. In other words, Pakad is the characteristic pattern or particular way in which a raga moves. Eg.The Pakad of Raga Durga is Sa Re Ma, Re Ma, Ma Dha, Ma Re Sa.
Prahar: Prahar is the particular time at which a raga is sung. One prahar is made of three hours. The day has four prahars starting at sunrise and the night has three prahars starting at sunset.
Sthayi:The first stanza of a composition in a raga is called the Sthayi. The literal meaning of the word Sthayi is fixed. Generally a sthayi is sung in the Madhya Saptak (middle octave region) of a raga.
Swar:Swar or Sur are the seven notes of the Hindustani Classical Music Scale. They are:
Shadaj - Sa
Rishabh - Re
Gandhar - Ga
Madhyam - Ma
Pancham - Pa
Dhaivat - Dha
Nishad - Ni Sa (Shadaj) and Pa (Pancham) are the Achala (Fixed) swar. These two are the tonal foundation for all Indian Classical Music. The other five swars areChala ie they have alternate forms. The Komal Swars or the flat notes are Re, Ga, Dha, Ni. The Teevra Swar or the sharp note is Ḿa. A swar is Varjit if it is omitted or not used in a Raga.
Swarmalika :A composition sung in a sargam is called a Swarmalika. There are two parts of the Swarmalika: Sthayi and Antara.
Thaat:The modal structure of a raga is called Thaat. It specifies which alternate forms of swar will be chosen.
Vadi - Samvadi Swars :Each raga has a Vadi, Samvadi, Anuvadi and Durbal Swar.
Vadi Swar is the most stongly emphasized note in a raga.
Samvadi Swar is a note which is strong but slightly less strong than theVadi Swar.
Anuvadi Swar is a note which is neither emphasized nor de - emphasized.
Durbal Swar is a note which is de-emphasized in a raga.
Varjit Swar is a note which is not there or excluded from a raga.
Vakra:Aroha and Avaroha may use certain characteristic twists and turns. Vakra are these prescribed twists.