" 

 :Yeah, concise to you, a physics major!  But I got here to find out what ""action"" is so I can understand ""Lagrangian"".  However, what I got from this is: ""action is the integration of the Lagrangian across time"", which, being circular, tells me nothing other than that I'm even stupider than I already knew I was.  GIVE EXAMPLES please—even obscure ones, if that's the best you can do for an obscure topic. 

 :Hey, I'm just sayin'...   

 : "