Definition of that is (to say)
- We—that is to say my wife and I—will be attending the wedding.
- We plan on going to the concert—that is, if tickets are still available.
: to express in words : state
: to state as opinion or belief : declare
: utter, pronounce
: something that is said : statement
: an expression of opinion
: a right or power to influence action or decision
: about, approximately
: for example : as
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