backlog - The main source of information about the project is the Product Backlog, which defines requirements the application must meet in order to be successful. Requirements are expressed as user stories of the format: “As a: I want to: So I can: ”
blocker - Any issue or task that is preventing the project from moving forward or is preventing another task from being able to be started.
burndown chart - A graphical view of the number of stories in the backlog that have been completed against the total number remaining across sprints.
sprint - Application development cycles lasting from one to four weeks. Sprint length is fixed across the life of the project and is chosen by the team. A fixed number of user stories are assigned to each sprint. This is not to say that stories cannot be added to the sprint. Just that they can’t be added if doing so exceeds the capacity of the team to create, test, and deploy a working application by the end of the sprint.
story points - A measure of relative effort or difficulty required to complete a given story. Part of the backlog grooming process is for the Scrum Team to review user stories and estimate the number of story points required for each one. There are many different methods that can be used for this and the one chosen by the Scrum Team isn’t as important as the need to be consistent when estimating story points.
velocity - Measures the average rate that stories are completed across sprints. The basic method is to divide the number of story points completed by the total number in the product backlog. Over time velocity is a measure of the work that can be expected to be completed in a sprint and it is used to ensure that the team doesn’t overcommit the number of story points to be completed in a given sprint.