(1) Compensation for services, including fees, commissions, fringe benefits, and similar items;
(2) Gross income derived from business;
(3) Gains derived from dealings in property;
(4) Interest;
(5) Rents;
(6) Royalties;
(7) Dividends;
(8) Annuities;
(9) Income from life insurance and endowment contracts;
(10) Pensions;
(11) Income from discharge of indebtedness;
(12) Distributive share of partnership gross income;
(13) Income in respect of a decedent; and
(14) Income from an interest in an estate or trust.
For items specifically included in gross income, see part II (sec. 71 and following). For items specifically excluded from gross income, see part III (sec. 101 and following).