-ation

-ation

suff.
1.
a. Action or process: strangulation.
b. The result of an action or process: acculturation.
2. State, condition, or quality of: eburnation.

[Middle English -acioun, from Old French -ation, from Latin -ātiō, -ātiōn-, n. suff. : -ā-, stem vowel of verbs in -āre + -tiō, -tiōn-, abstract n. suff.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

-ation

suffix forming nouns
indicating an action, process, state, condition, or result: arbitration; cogitation; hibernation; moderation. Compare -ion, -tion
[from Latin -ātiōn-, suffix of abstract nouns, from -ātus -ate1 + -iōn -ion]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

-ation

a suffix used to form nouns corresponding to verbs or adjectives ending in -ate1 (separation); on this model, sometimes used to form nouns from other stems (flirtation; starvation).
[< Latin -ātiōn-, s. of -ātiō=-ā- s. vowel + -tiō -tion]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.