cline
1 of 2noun
ˈklīn 
: a gradient of morphological or physiological change in a group of related organisms usually along a line of environmental or geographic transition
clinal
ˈklī-nᵊl
adjective clinally
ˈklī-nə-lē
adverb -cline
2 of 2noun combining form
: slope
monocline
Word History
Etymology
Noun
Greek klinein
Noun combining form
back-formation from -clinal
First Known Use
Noun
1938, in the meaning defined above