Added 10 October 2026 half-year noun Categories: Obscure Words In Latin: sēmiennium Wiktionary noun ! Definition from Wiktionary (CC BY-SA). More about half-year at Wordnik → Where our words come from → The period of time equal to half a year; normally referred to as 6 months, but a half-year is more exactly 182.5 days (without a leap day) Origin From half- + year. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: halfmonthsemimonthlysemesterhalf-timehalfthhalf-centuryhalf-hourmidyearone-halfsemestre Back to today's word