Final answer:
Capital interest in a partnership refers to the bundle of economic rights a partner receives for their investment in the partnership, such as the right to a share of the profits, losses, and assets.
Step-by-step explanation:
The definition of capital interest in a partnership is 3) The bundle of economic rights a partner receives for his investment in a partnership. Capital interest refers to the partner's contribution of assets, usually in the form of money, property, or services, to the partnership. This contribution gives the partner the right to a share of the partnership's profits, losses, and assets.