Definitions of public issue and investor categories clarify instruments, participants and eligibility under the ICDR framework. Regulation 2 supplies operative definitions for public and rights issues, investor classifications, issuance mechanisms and key participants under the SEBI ICDR framework. It specifies covered instruments as equity shares and convertible securities, defines processes and roles such as book building, ASBA, book runner, green shoe option and stabilising agent, and categorises investors including qualified institutional buyers, non institutional investors and retail investors. It also defines issuer status, promoter and promoter group composition, corporate officers, wilful defaulter and systemically important NBFC, and incorporates amendment-based refinements and cross-references to other statutes.