i) a person by whom any tax or any other sum of money is payable under income tax act.
ii) Every person in respect of whom any proceeding under this act has been taken for the assessment of his income or loss or the amount of refund due to him.
iii) a person who is assessable in respect of Income or loss of another person
iv) Every person who is deemed to be an assessee under any provision of this act
v) A per person who is deemed to be an assessee in default under any provision of Income-tax act e.g a person who was liable to deduct tax but has failed to do so, shall be treated as an assessee in default