A processes for delivering productive software by translating product ideas into delivered features. SDLC is a life cycle because of the feedback loop of bugs and users that return from delivered software.
Product Strategy -> Product Managers -> Ideas -> SDLC -> Features
JIRA is a ubiquitous tool for tracking the SDLC, particularly within Scrum and Agile processes. On top of JIRA there are also higher level delivery tracking tools and metrics.