from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A gradual change in a character or feature across the distributional range of a species or population, usually correlated with an environmental or geographic transition.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A gradation in a character or phenotype within a species or other group.
- n. Any graduated continuum.
From Greek klīnein, to lean.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek κλίνειν (klínein, "to lean, incline") (from which also climate), from Proto-Indo-European *ḱley- (English lean). (Wiktionary)