What does Prax stand for?

Bowns Practice (or Precedents) in Chancery - A publication (SAUS)

Browns Practice or Precedents in Chance (SAUS)

Brown's Practice (Praxis) - or Precedents in Chancery - A publication (DLA)

First Union Rail - Private rail car owner code

Praxis Pharmaceuticals, Inc. (SAUS)

Premier Agricultural - Federal Railroad Administration identification code