What is the difference between slacks and pants? (Women's clothing in particular)

Agree with this. A couple of other things, construction-wise:

If the waistband is made out of two pieces of fabric instead of one, probably slacks.

If the stitching at the hemline is visible, probably not slacks.

Actually, a superhero would wear underpants under his pants (no good superhero’s goin commando), then underpants over his pants, then trousers over those outer underpants for sake of his secret identity.

Man, they must get swamp crotch somthin fierce. No wonder Superman lives at the north pole. (south pole post crisis)