Front clip ?

[Train]

What exactly does this mean ?

 

[1968FormulaS340]

Normally it means all the sheet metal (+ or - trim) from the doors forward.

Fenders

Hood

Grill surround/valance

And so on…….

 

[cudamark]

It usually means everything forward of the firewall including inner fenders, K-member, suspension, frame rails, and radiator core support. If you don't need those welded-in items, it's called an "unbolt front end".