B737 NG - VNAV vs LNAV Arming criteria on ground
 

Hello


One of the VNAV arming criteria on ground is :

• A valid flight plan has been entered

One of the LNAV arming criteria on ground is :

• An active route in the FMC

Can some one please explain what is the difference between " A valid flight plan" and " An active route"

I understand active meaning route entered and executed, but what is the difference between flight plan and route?

Regards