/ ˈgreɪdiənt; NAmE / noun
1.
(also grade especially in NAmE ) the degree to which the ground slopes, especially on a road or railway :
a steep gradient
a hill with a gradient of 1 in 4 (or 25%)
2.
( technical ) the rate at which temperature, pressure, etc. changes, or increases and decreases, between one region and another
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WORD ORIGIN
mid 19th cent.: from grade , on the pattern of salient .