also known as
Known by another name or description. Often abbreviated "AKA" or "a.k.a." both in speech and in writing. The Affordable Care Act, also known as "Obamacare," came into effect in 2014.
(if the) truth be known
I must admit; to be honest; in actuality. Truth be known, even though I majored in English literature, I've never read anything by Hemingway! I know I said I wanted to go out to the bars tonight, but if the truth be known, I'd rather just stay home and watch a movie.
if the truth were known
Prov. if people knew how something really was, instead of how it appears to be. If the truth were known, people wouldn't shop at that store. Its owners aren't as honest as they seem. Sam: You're always polite to Fred, but you don't really like him, do you? Alan: Well, no, if the truth were known.
knew it was coming
and (had) known it was comingto have expected in advance that something was to happen. I shouldn't act surprised. I knew it was coming. It's his own fault. He should have known it was coming.
known fact
something that is generally recognized as a fact. That grass is green is a known fact. It is a known fact that John was in Chicago on the night of the murder.
known quantity
someone whose character, personality, and behavior are recognized and understood. We need not worry about how John will behave. He is a known quantity. Lisa is a known quantity and I am sure she will not surprise us by voting with the opposition.
man is known by the company he keeps
Prov. A person tends to associate with people who are like him or her. Son, when you go away to school, spend your time with serious people; don't hang around with people who go to parties all the time. A man is known by the company he keeps. If you want to know what kind of person George is, look at his friends. A man is known by the company he keeps.
tree is known by its fruit
Prov. People judge your character by what you do. (Biblical.) The politician may say she believes in more spending on child care, but the tree is known by its fruit; she hasn't voted for a single measure that would help.