In this note, a historical view on the Bejan numbers (Be) is presented. There are two definitions of Bejan number (Be) in the field's of thermodynamics, fluid mechanics, heat transfer, and mass transfer. A general form of Bejan number (Be) is introduced, and application of Bejan number (Be) to flows in porous media is shown. The note concludes with a critical discussion of the view that Bejan number in convection (Be) is the combination of the Euler (Eu) and Reynolds (Re) numbers. (C) 2015 Elsevier Ltd. All rights reserved.