Re-Ranking
Re-ranking is a second ranking pass applied to an initial set of search results — often using a more precise but more expensive model — to reorder just that shortlist rather than the entire catalog.
Part of Ranking Optimization
Running an expensive ranking model against an entire catalog for every query is often too slow; re-ranking splits the work into a fast first pass that narrows results down to a manageable shortlist, then a slower, higher-quality pass that reorders only those candidates.