The Trade Unions Act, 1926
“Trade Union” means any combination, whether temporary or permanent, formed primarily for the purpose of regulating the relations between workmen and employers or between workmen and workmen, or between employers and employers, or for imposing restrictive conditions on the conduct of any trade or business, and includes any federation of two or more Trade Unions:
Provided that this Act shall not affect—
(i) any agreement between partners as to their own business;
(ii) any agreement between an employer and those employed by him as to such employment; or
(iii) any agreement in consideration of the sale of the goodwill of a business or of instruction in any profession, trade or handicraft.