The story of the name, from the sources

In Maqayis al-Lugha, Ibn Faris says the root za-ha-ra has one meaning: beauty, light and clarity. From it come zahr, the blossom of every plant; al-zuhara, the star; and al-azhar, the moon.
“a single root meaning beauty, light and clarity”
zahr: the blossom of every plant · al-zuhara: the star “al-azhar: the moon”
Ibn Faris
Maqayis al-Lugha · vol. 3, p. 31
Al-Jawhari's al-Sihah says: a man is azhar, white and bright of face, and a woman is zahra. And in al-Qamus al-Muhit, al-zahra is the woman whose face shines.
“a man is azhar, white and bright of face, and a woman is zahra”
“al-zahra: … the woman whose face shines”
al-Sihah · vol. 2, pp. 674–675 · al-Qamus al-Muhit · vol. 1, p. 403

Lisan al-Arab holds a surprise: the suras al-Baqara and Al Imran are the two zahras, the two that shine and give light; each of them is a zahra. In Sahih Muslim, the Prophet, peace be upon him, said: recite the two zahras, al-Baqara and Surat Al Imran.
الزَّهْراوان
“the two that shine and give light; each of them is a zahra”
“Recite the two zahras: al-Baqara and Surat Al Imran”
Lisan al-Arab · vol. 4, pp. 331–333 · Sahih Muslim 804

Then al-Zahra became a title and a city. Ibn Hajar writes of Fatima, daughter of the Messenger of God, peace be upon him, may God be pleased with her: she was given the title al-Zahra. And Taj al-Arus names al-Zahra, a city in al-Andalus near Cordoba, built by al-Nasir, one of the most wondrous of cities.
A title: “she was given the title al-Zahra” · Fatima, daughter of the Messenger ﷺ
al-Zahra
“in al-Andalus, near Cordoba, one of the most wondrous of cities”
Ibn Hajar, al-Isaba · vol. 8, p. 262 · Taj al-Arus · vol. 11, pp. 473–483




