The definition of a double take is a delayed reaction to a remark or a situation where you are surprised causing you to look twice.
(noun)1. An example of a double take is when you think you see a famous celebrity standing right next to you on the street and you are really surprised but sneak another glance. 2. An example of a double take is your amazed reaction when your parents tell you they are getting a divorce.
See double take in Webster's New World College Dictionary
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See double take in American Heritage Dictionary 4