degree-day

or de·gree day

[ dih-gree-dey ]

nounEngineering.
  1. one degree of departure, on a single day, of the daily mean temperature from a given standard temperature. Abbreviation: dd

Origin of degree-day

1
First recorded in 1925–1930

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

British Dictionary definitions for degree day (1 of 2)

degree day

noun
  1. a day on which university degrees are conferred

British Dictionary definitions for degree-day (2 of 2)

degree-day

noun
  1. a unit used in estimating fuel requirements in heating buildings. It is equal to a fall of temperature of 1 degree below the mean outside temperature (usually taken as 18°C) for one day

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

Scientific definitions for degree-day

degree-day

  1. A unit of measurement equal to a difference of one degree between the mean outdoor temperature on a certain day and a reference temperature. The unit is most often used in estimating the energy needs for heating or cooling a building (for example, heating degree-days and cooling degree-days). Originally, degree-days were used to determine the relationship between temperature and plant growth. The term continues to be used in life sciences as a measure of upper- and lower-temperature limits for organisms.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.