preemptive right n1 : right of first refusal
2 : the right of a shareholder to buy shares of newly issued stock in proportion to existing holdings before a public offering is made in order to prevent dilution of ownership interest or seizure of majority control by management
Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.