What are the actual differences between infectious diseases and contagious disease? any answers appreciated!

Contagious disease: By definition - contagious means you're liable to 'catch' something from someone else. I think of 'the flu', chickenpox, 'meningitis' as good examples of that. (So always good to practice hygiene!). Whereas infectious diseases encompasses all that PLUS other diseases caused by 'germs' that may not necessarily be contagious: for example those deadly amoeba that kill kids every summer, Lyme dz etc.