What does looping the D-Line mean?

Hello,

I've been hearing this about some blitz setups on the edges but I don't know what they are talking about. Are they referring to crash left/right or contain or something esle?

it means taking a LB or a cb, and running around the d-line for the sack or forced throw

Incorrect, it's when the linemen move towards the gaps. That's why you see people loop them and then reblitz certain lineman, so a DT can confuse a guard and Center, taking away an essential blocker for the offense. But no, I'm not sure i fyou contain, spread, or whatever.