I was watchin a vdo lesson other day on modal music and there it says
"one note tht is different between E maj and E lydian tht is #4"
for ex: Between E maj and E lydian A# is the note which is different

what does it really mean ?

thnx !

P.S: its on a dvd so im unable to put up any vdo link.
E major has an A, E Lydian has an A#.

major = 1 2 3 4 5 6 7

Lydian = 1 2 3 #4 5 6 7
that in Emajor its A... in E lydian its A#.... its right in front of ya... just have to read it... u typed it yrself too.
It means that E Lydian has an A# (or a #4) in it... and E Major does not.

Maybe you should give the modal music a rest for now and come back to tonal harmony and make sure you really understand the Major/Minor scales.
thnx a bunch guys! i wasn't takin into account tht E lydian is the root note here and A# is the 4th degree whereas in Emaj, A is the 4th degree. stupid error really.