• noun sixty minutes of work


  • A unit of time equal to 3600 seconds. Its abbreviation is h, or hr.
  • symbolh
  • abbreviationhr

Information & Library Science

Origin & History of “hour”

Greek hṓrā (a distant relative of English year) was originally a rather vague term, denoting ‘period of time, season’. In due course it came to be applied more specifically to ‘one twelfth of a day (from sunrise to sunset)’, but as this varied in length according to the time of the year, hṓrā was still far from being a precise unit of time. Not until the middle Ages (when hṓrā had passed via Latin hora and Old French hore into English as hour) did the term become fixed to a period of sixty minutes. (The same sort of vague relationship between ‘time’ in general or ‘period of time’ and ‘fixed period’ is shown in Swedish timme, which is related to English time but means ‘hour’; in German stunde, which originally meant ‘period of time’, but now means ‘hour’; and indeed in English tide, which in Old English times meant ‘hour’ but now, insofar as it survives as a temporal term, denotes ‘season’ – as in Whitsuntide.) English horoscope (16th c.) comes ultimately from Greek hōroskópos, a compound which meant literally ‘observer of time’ – that is, of the ‘time of birth’.