Swimlanes are the horizontal counterparts to the columns on a board. Unlike columns, which are always mapped to issue statuses, you can base your swimlanes on several criteria:

• Queries: These are Jira search queries constructed with JQL. With this option, each swimlane will only show results from its own query. For example, you can create a query for each priority value, so you can group your issues based on their importance.
• Stories: Each swimlane will be mapped to a story. All subtasks that fall under the story will be displayed in the swimlane.
• Assignees: Each swimlane will be mapped based on the issue's assignee.
• Epics: Each swimlane will be mapped to an epic. All issues that fall under the epic will be displayed in the swimlane.
• Projects: Each swimlane will be mapped to a project. If there is only one project, there will be only one swimlane.
...