What it means
Agile is an approach, not a single method. It comes from the Agile Manifesto of 2001, which values individuals and interactions, working software, customer collaboration and responding to change. Scrum and Kanban are frameworks that put it into practice. Scrum uses fixed sprints, and Kanban uses a continuous board with limits on work in progress. Waterfall, its nearest neighbour, plans the full scope first and delivers at the end.
Why it matters when you buy software
Many project management tools call themselves agile, but the label covers different features. Check whether the plan includes sprints, backlogs, boards, burndown reports and roadmaps, and which pricing tier carries them. A team that works to fixed phases and deadlines may need Gantt charts and dependencies more than sprint tools.
How it works in practice
A team keeps a backlog of work items, picks a batch for a short cycle, usually one to four weeks, and reviews the result at the end. Software shows this as boards, sprint planning views and progress charts. Priorities change between cycles as feedback arrives.
See also: Gantt chart, Kanban and the glossary index.