To lie or to fib? That is the question!

So today my very smart 5 year old Rocco, was trying to find my ipod to listen to. I use it for the gym or when I go for a run, so I do have to admit that there may be some inappropriate songs for a 5 year old or maybe even a 30 year old!! He particularly likes one song by pink, so I occasionally let him listen to it! So today he tells me he needs my ipod headphones to listen to his tag reader (leap frog) so it won't be SO loud.... RIGHT!! I tell him where the ipod is hiding so he could get the headphones... Turns out he wants the ipod! Anyways I asked him why he lied to me about needing the headphones for the tag reader...., "mommy, I wasn't lying, I was fibbing!" "please don't say I was lying, that is SO bad!". Is there really a difference between a lie and a fib? I guess it just sounds better!