Biology. the gradual change in certain characteristics exhibited by members of a series of adjacent populations of organisms of the same species.
Linguistics. (in systemic linguistics) a scale of continuous gradation; continuum.
1935–40; < Greek klī́nein to lean 1
In biology, a cline is a gradual change in a trait or characteristic across a population of a species. This gradient occurs over a geographic area where environmental factors, such as altitude or temperature, vary. One example of a cline is the variation in zebra stripes across Africa. In the North, zebras have bold, black-and-white stripes over their entire bodies. Moving south, the stripes become fainter and more brownish-gray. In the most southern regions, their stripes are even more faded, and the lower legs are solid white. In a cline, there is no abrupt, sudden change; rather, traits change gradually across a spectrum based on the animal's geographic range.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
If there is gene flow between the populations, the individuals will likely show gradual differences in phenotype along the cline.
From Textbooks ● Jun. 9, 2022
A cline is the specific set of traits in a population of a given species that have been influenced by the local environment.
From Textbooks ● Jun. 9, 2022
Using other databases, researchers had found that the number of genes that contribute to tallness in Europeans increased on a cline from south to north.
From Science Magazine ● Jan. 3, 2019
Van Tuyl and Pereltsvaig make much of the fact that the global cline in phonemic diversity does not hold within all continents.
From Science Magazine ● Feb. 9, 2012
This is a result of the cline mentioned above and does not indicate relationship with modestus.
From Subspeciation in the Meadow Mouse, Microtus pennsylvanicus, in Wyoming, Colorado, and Adjacent Areas by Anderson, Sydney
Apa's famous friends left apparent messages of support under his post, including his Map That Leads to You co-star Madelyn Cline, who wrote: "Identify theft is not a joke."
From BBC ● May 7, 2026
The site is the second-largest gas field in the world, according to British energy consultancy Gaffney, Cline and Associates, behind only South Pars, shared by Iran and Qatar.
From Barron's ● Apr. 21, 2026
This sentimental and self-indulgent social-dance affair to musical selections from Antonín Dvořák, Patsy Cline, Billy Joel, Stevie Wonder and Donna Summer goes nowhere, repeatedly.
From The Wall Street Journal ● Nov. 17, 2025
Cline De La Rosa said this is the general address used to report fires in the riverbed but does not mean they are in the exact same location.
From Los Angeles Times ● Jan. 21, 2025
Cline passed the news up the ladder to McGeorge Bundy, Kennedy’s national security adviser.
From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
