[ loo-muh n-ouuh r, -ou-er ]
/ ˈlu mənˌaʊər, -ˌaʊ ər /
a unit of luminous energy, equal to that emitted in 1 hour by a light source emitting a luminous flux of 1 lumen. Abbreviation: lm-hr
Words That Command RespectRead more in this article about some frequently asked questions and fun facts related to our definitions.
Why Did “Noon” Used To Mean 3:00? To most, the word noon signifies a specific time of day–namely, 12:00 midday, a.k.a. “lunchtime.” The counterweight to 12:00 midnight. But, surprisingly, the term noon wasn’t always shorthand for midday at 12:00; in fact, it used to refer to a different time of day altogether. First, some essential background. Clocks and watches are relatively new inventions. Though some timekeeping devices, like sundials and water clocks, …
Origin of lumen-hour
First recorded in 1920–25
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019