Aggregate Rating
An aggregate rating is the averaged score across every review of a product, and the schema.org property of the same name that lets search engines render that average as a star snippet beside a listing, summarising many ratings into one citable number.
As a metric, the aggregate rating collapses all of a product page's reviews into a single figure, usually shown as a value out of five next to a review count. As schema.org markup, the aggregateRating type carries that figure in a machine-readable form, and it is the piece search engines read when deciding whether to draw rating stars under a result.
Google requires the markup to include a ratingValue and either a reviewCount or ratingCount, and it enforces a strict rule: the count and value in the structured data must match the reviews actually visible on the page. Marking up a rating that a shopper cannot see, or inflating the count, is against policy and can cost you rich results entirely, so the safe path is to generate the markup from the same reviews you display.
Getting existing reviews readable, corroborated, and cited by search and AI is the gap BetterReviews closes, and a correct aggregateRating is the mechanism that turns honest review counts into the star snippets and answer-engine citations that earn the click.