Ya Zahra

Imam Ja'far ibn Muhammad al-Sadiq (A.S) was once asked:

"as to why Janabe Fatima (S.A) was called Zahra? He (A.S) said that when she used to stand under the arch (Mehraab) for offering prayers, her radiance used to shed light for those high up in the skies in the same manner as the stars shed their light on the earth for the benefit of it's inhabitants"

Behaar, Maani-ul-Akhbaar and Elal- ush-Sharaaye