Otto Pilot,

You and I are on the same page. I think based on the definitions you provided, the official meaning is someone who crosses a picket line, whereas the one who engages in lower than union wages is more slangy and possibly a bit of a stretch.

If we went with the slangy term, again - we'd be calling JB and VA pilots scabs.

Again - both actions are incredibly harmful to the profession... but the argument can be made that crossing a picket line is MUCH lower and more despicable than "working for less than union wages" - the latter of which many union and non-union airlines have engaged over the last several years.