a combination of -ate1. and -ion, used to form nouns from stems in -ate1, (separation); on this model, used independently to form nouns from stems of other origin:
starvation.
Origin
< Latin-ātiōn- (stem of -ātiō), equivalent to -ā- stem vowel + -tiōn--tion
British Dictionary definitions for -ation
-ation
suffix
1.
indicating an action, process, state, condition, or result: arbitration, cogitation, hibernation, moderation Compare -ion, -tion
Word Origin
from Latin -ātiōn-, suffix of abstract nouns, from -ātus-ate1 + -iōn-ion
Word Origin and History for -ation
word-forming element for making nouns of action; see -ion.