No, it's not Fiza. It's Khiza, or rather, Khizaan.
Anyway, the meaning of Khiza is Autumn. It's the season when there are no leaves or flowers on trees and in poetry or lyrics or songs, it's used to tell the time of doom, gloom and sadness.
So next time a singer sounds like Khiza, don't think it's Fiza. S/he's most probably right. :)