Hello Tatyana, "It's a given" or "that's a given" means that a basic fact that you accept as being true. it is a sure thing that you don't need to prove it. I think it comes from mathematics, you must be very familiar with how we solve the math problems. "x+y=10, it is given that x=3, What is the y?" In this example, 'x=3' is given. In real life, an obvious thing or a sure thing is a given. it is prior knowledge, an basic fact. you can also use "it goes without saying..." or"everybody knows..." depending on the context. It goes without saying that nothing is certain but death and taxes It is a given that nothing is certain but death and taxes. Everybody knows that nothing is certain but death and taxes. There is no denying that nothing is certain but death and taxes.

It is like 'it goes without saying'. It means that something that is already well known and understood ahead of time, without verifying it. Eg: It's a given that junk food is not good for health.

It means that there is a common agreement that something is true. I hope this is helpful. Have a good day. www.MissionQuest.org