Product Backlog
In plain terms
The prioritized master list of everything a product needs.
Going deeper
The product backlog is the single, ordered source of all desired features, fixes, and work for a product, owned by the Product Owner. It drives what gets built.
Under the hood
Continuously refined and reprioritized; sprint backlogs draw from its top items.
Examples
Feature lists, prioritization, Product Owner, Scrum, roadmap input.
Think of it like...
Like a master wish list, ranked, from which the team builds the most valuable items first.