Saara is a variation of Sarah, which is a feminine Hebrew name meaning 'Princess'. The name is very popular all over the world and has developed lots of variants in lots of languages.
Kausar is a Muslim given name for males or females, which means "abundance" or "a river or lake in paradise". The name is a reference to Hauzu'l-Kausar, a sacred lake called the "pond of abundance" in Paradise in the Quran.
