1) The process of adding new user stories to the backlog, re-prioritizing existing stories as needed, creating estimates for previously un-estimated stories, and decomposing large stories into smaller stories or tasks. Backlog grooming is both an ongoing process and the name for a meeting (see definition 2).
Scrum trainer and consultant Roman Pilcher explains the significance of Backlog Grooming to the Agile development process: “Grooming the product backlog collaboratively creates a dialogue within the Scrum team and between the team and the stakeholders. It removes the divide between “the business” and “the techies.” It eliminates wasteful handoffs, and avoids miscommunication and misalignment. Requirements are no longer handed off to the team; the team members co-author them. This increases the clarity of the requirements, leverages the Scrum team’s collective knowledge and creativity, and creates buy-in and joint ownership.”
2) A meeting or ceremony that occurs regularly within a team’s iteration cycle. Scrum Alliance founder Ken Schwaber recommends that teams allocate 5% of their time to revisiting and tending to the backlog. Backlog grooming is the term favored by the Scrum Alliance, although Scrum co-founder Jeff McKenna and Australian CST Kane Mar prefer to call this ceremony Story Time.