SDLC stands for Software development life cycle. It'sdefined by various books/persons in their own way,but the basic concept is that SDLC defines the whole software development process in terms of various phases involved in the development of any particular software. Phases of SDLC(Software Development Life Cycle): 1.Requirement Gathering...done mostly by the (BA)business analysts. 2.Feasiblity study/Analysis...done by the project managers,BA. 3.Design...........prepared by SSE(Project managersSenior software developers,Database architects,) a)HLD...High Level design...generally prepared by project managers with 8-10 years of experience. b)LLD..Low level design...generally prepared by sse with 3-5years of experience. 4.coding....by development team. 5.testing...by testing team. 6.implementation...by implementation team. 7.maintenance..free initially and chargeable to the client in long run. Now,these are the basic and compulsory phases of SDLC.But there may be some different betwwen no. of phases in various models of sdlc. Models of sdlc: 1.waterfall model 2.V-model 3.Spiral model 4.prototype model 5.Agile model. there are some other models also,but the above mentioned models are mainly used in the industry and are sufficient for explaining in interviews. Hope this answer is useful.If some one finds any mistake then please comment.