What is an Epic?
An epic is a body of work too large to finish in one sprint — a container that gets progressively broken into user stories as it approaches the top of the backlog. Epics let you plan big without detailing everything early: the hierarchy runs theme/initiative → epic → story → task.
Healthy backlogs are shaped like icebergs: detailed stories at the top, chunky epics below, and giant vague ones at the bottom — refined just-in-time, never all-at-once.
Worked example
"Multi-currency support" sits in a fintech backlog as one epic for a quarter. When its turn nears, refinement splits it: display balances in EUR (story), FX conversion at transfer (story), regulatory reporting per currency (story, later an epic of its own — it happens). Nobody wrote those details three months early, and nothing written early was wasted.