Unit definition clarified as including beneficial interests, shares and partnership interests under income tax law. Definition focuses on the meaning of unit for income tax purposes, encompassing a unit of a business trust, a unit defined for dividend/distribution tax provisions, and the beneficial interest of an investor in an Alternative Investment Fund, and expressly including shares or partnership interests; for investment fund specific provisions, it similarly means the beneficial interest of an investor in the fund or a scheme of the fund and includes shares or partnership interests.