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[sur-tn-lee] /ˈsɜr tn li/
with certainty; without doubt; assuredly:
I'll certainly be there.
yes, of course:
Certainly, take the keys.
surely; to be sure:
He certainly is successful.
Origin of certainly
Middle English word dating back to 1250-1300; See origin at certain, -ly Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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  • She certainly knew he was liable to go at any time, in exactly the way he did go.

    The Spenders Harry Leon Wilson
  • I certainly did need you to come along right now and set me straight.

    The Spenders Harry Leon Wilson
  • Too bad, though—you certainly need a wife to take the conceit out of you.

    The Spenders Harry Leon Wilson
  • "certainly, Robert," was the reply, but the lawyer's manner showed some surprise.

    Brave and Bold Horatio Alger
  • "You certainly do know your business, son," said Uncle Peter, fervently.

    The Spenders Harry Leon Wilson
British Dictionary definitions for certainly


with certainty; without doubt: he certainly rides very well
sentence substitute
by all means; definitely: used in answer to questions
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for certainly

c.1300, in all main modern senses, from certain + -ly (2).

Online Etymology Dictionary, © 2010 Douglas Harper
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