• synonyms


[lawng-dey, long-]
adjective Botany.
  1. requiring a long photoperiod in order to flower.
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Origin of long-day

First recorded in 1915–20
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for long-day

Historical Examples of long-day

  • With our present arrangement, we had these long-day marches every other day.

    The South Pole, Volumes 1 and 2

    Roald Amundsen

  • As he hastened out to trail the long-day bitter enemies, he was framing in his mind the preliminary answers for the coroner.

    Laramie Holds the Range

    Frank H. Spearman

  • So in general our winter work was about as restless and trying as that of the long-day summer.

British Dictionary definitions for long-day


  1. (of certain plants) able to mature and flower only if exposed to long periods of daylight (more than 12 hours), each followed by a shorter period of darknessCompare short-day
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012