Zero-Result Search
A zero-result search is a storefront search query that returns no matching products, even though the catalog may contain items a shopper would consider relevant.
Part of Zero Result Searches
It differs from a search that returns low-quality or irrelevant results, because the results grid comes back completely empty — a state that's easy to detect and count directly from search logs. Zero-result searches typically stem from vocabulary mismatches between how shoppers phrase a query and how products are titled or tagged in the catalog.
Example
A shopper searches "trainers" on a store that only tags its footwear as "sneakers" — no results match, even though matching products exist.