degree-day

or de·gree day

[ dih-gree-dey ]

noun

, Engineering.

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

degree-day

¹

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

degree day

²

noun

1. a day on which university degrees are conferred

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.

Word History and Origins

Origin of degree-day¹

First recorded in 1925–1930

Example Sentences

The growers look at degree-day counts — what’s the average temperature each day, how much warmth are we getting — that will affect how fast the crop develops.

From Seattle Times

He had been known to expostulate with some of his more reckless masters upon the absurdities of their goings-on; and had more than once had a commons of bread flung at his head, when taking the opportunity of symptoms of repentance, in an evident disrelish for breakfast, to hint at the slow but inevitable approach of "degree-day."

From Project Gutenberg

He had been known to expostulate with some of his more reckless masters upon the absurdities of their goings-on; and had more than once had a commons of bread flung at his head, when taking the opportunity of symptoms of repentance, in an evident disrelish for breakfast, to hint at the slow but inevitable approach of “degree-day.”

From Project Gutenberg