[grey-dee-uhnt]
noun
1.
the degree of inclination, or the rate of ascent or descent, in a highway, railroad, etc.
2.
3.
Physics.
a.
the rate of change with respect to distance of a variable quantity, as temperature or pressure, in the direction of maximum change.
b.
a curve representing such a rate of change.
4.
Mathematics. a differential operator that, operating upon a function of several variables, results in a vector the coordinates of which are the partial derivatives of the function. Abbreviation: grad. Symbol:
5.
rising or descending by regular degrees of inclination.
6.
progressing by walking; stepping with the feet as animals do.
7.
of a type suitable for walking or running, as the feet of certain birds; gressorial.

Origin:
1635–45; < Latin gradient- (stem of gradiēns), present participle of gradī to walk, go, equivalent to grad- walk + -i- thematic vowel + -ent- -ent

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Collins
World English Dictionary
 gradient (ˈɡreɪdɪənt) —n 1. Also called (esp US): grade a part of a railway, road, etc, that slopes upwards or downwards; inclination 2. Also called (esp US and Canadian): grade a measure of such a slope, esp the ratio of the vertical distance between two points on the slope to the horizontal distance between them 3. physics a measure of the change of some physical quantity, such as temperature or electric potential, over a specified distance 4. maths a.  (of a curve) the slope of the tangent at any point on a curve with respect to the horizontal axis b.  curl Compare divergence (of a function, f(x, y, z)) the vector whose components along the axes are the partial derivatives of the function with respect to each variable, and whose direction is that in which the derivative of the function has its maximum value. Usually written: grad f, ∇f or ∇f —adj 5. sloping uniformly [C19: from Latin gradiēns stepping, from gradī to go]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
Etymonline
Word Origin & History

"steep slope of a road or railroad," 1835, principally in Amer.Eng., from grade (q.v.) by analogy of quotient, etc.
Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
American Heritage
Medical Dictionary

n.

1. The rate at which a physical quantity, such as temperature or pressure, changes relative to change in a given variable, especially distance.

2. A series of progressively increasing or decreasing differences in the growth rate, metabolism, or physiological activity of a cell, an organ, or an organism.

The American Heritage® Stedman's Medical Dictionary
Cite This Source
American Heritage
Science Dictionary
 gradient   (grā'dē-ənt)  Pronunciation Key  (click for larger image in new window) The degree to which something inclines; a slope. A mountain road with a gradient of ten percent rises one foot for every ten feet of horizontal length. The rate at which a physical quantity, such as temperature or pressure changes over a distance. A operator on scalar fields yielding a vector function, where the value of the vector evaluated at any point indicates the direction and degree of change of the field at that point.
The American Heritage® Science Dictionary