SDLC-(Software development life cycle)- SDLC are the different stages of developing a software or it is a step by step procedure to develop a s/w.
1-Requirement → 2-Feasibility study → 3-design (high level design, low level design) → 4-coding → 5-testing → 6-installation/deployment → 7-Maintenance.
1-Requirement- in this stage the complete needs of a customer will be collected in the form of requirement document.
2-Feasibility Study- in this phase based on requirement it is analysed whether the project is feasible or doable wrt time, cost, resources and technology. All imp people like finance dept, HR, architect, BA and PM will do the feasibility study.
3-Design- in this phase a blueprint of the requirement is developed in the form of HLD or LLD.
4-Coding- Once design is completed a set of people known as developers will start writing the code or programs according to requirements.
5-Testing- once coding is completed i.e. an application is developed it should be tested if it is working according to the requirements or not. This process of testing the application according to the requirement is called as testing and this task is performed by test engineer.
6-Installation- Once the application is tested, developed and stable it should be installed at customer place.
7-Maintenance- Once the application is installed at the customer place it is possible that they may face some issues and these issues may be fixed immediately by the company by giving them support for certain period of time. This phase is called as Maintenance.
Source: http://selenium-makeiteasy.blogspot.com