Knickers vs full length

[BleeckerSt_Girl]

And what is the difference between capri length and knickers?

I don't know that there is any....except that in my mind when I see the term 'knickers' I think biking and with a chamois. It might be just in my mind though. It might be a regional thing, too.
All I really mean is stretchy leggings that end below the knee or around the calf area.