https://youtu.be/f7rLc7mx000?t=141 2mins21seconds it just sounds like it means something more than just checking no ?

It literally just means that you check and your opponent also checks. Daniel's saying that since his opponent checked back they didn't have QQ+ and his JJ is good.

It just means to check in position (check when checked to).

If someone hits the ball in tennis, the other has to hit it back. If someone checks to you in poker, you have the opportunity to check it back.

When the player in position checks ("checks it back"), the hand moves on to the next street, or goes to showdown.
The player in position only gets the option to check if everyone else checked to him. If there had been a bet, his only options are call, raise, or fold. If the action is checked to him, his only options are bet or check. If someone checks it back on the flop, it means he decided to not bet, so now a turn card is dealt.
When someone checks back, it usually caps their range. If they had a strong hand in position, they'd usually bet for value, because they should want to put money in the pot. If they had a draw, they'd usually bet as a bluff. So if they don't bet in position, they are saying "I don't want to bet for value or a bluff", so their hand is often of middling strength at best.

Checking back is just 'checking', but has a specific connotation, in that you are closing action with a check, a passive play. This can mean several things (it could mean you are trapping, it could mean you are unsure of where you stand and are trying to manage pot size, it could mean you missed and are giving up).

It is common for a player out of position to check his full range (especially if he was not the preflop aggressor), so his check is often not meaningful. Checking back a street is a little bit more meaningful (though that meaning can vary a lot based on context)

i looked into too much it is just simply checking back like ArtyMcFly example thank you guys