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Webster 1913 Edition
Isotherm
I′so-therm
,Noun.
[
Iso-
+ Gr. [GREEK] heat, fr. [GREEK] hot.] 1.
(Phys. Geog.)
A line connecting or marking points on the earth’s surface having the same temperature. This may be the temperature for a given time of observation, or the mean temperature for a year or other period. Also, a similar line based on the distribution of temperature in the ocean.