Added 9 October 2026 baseline /ˈbeɪslaɪn/ noun Categories: Describing WordsPlacesUncommon Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about baseline at Wordnik → Where our words come from → An imaginary line or standard by which things are measured or compared. the established a baseline for the budget The back line bounding each end of a tennis or handball court; when serving the server must not step over this line. The lines a baseball player must follow while running the bases. Origin From base + line. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: benchmarkbenchmarkingfootnotedatumlinerefreferencingdatabasereferencescenarioreferringrefer Back to today's word