Why is Abu Bakr (R) called Abu Bakr, when out of his sons none is named Bakr?

Question

Abu' basically means father. Then I was assuming why isn't any of his sons named 'Bakr'

Answer 1

Though it was a common practice for Arabs to use teknonyms (kunya) that directly referred to their eldest son, they did not always do so. In other words, it was relatively common to use a kunya (abu ...) with a name that did not belong to any of their children. Abu Bakr is one such name that sort of stuck and Abu Bakr was known to have liked and preferred it. Sometimes the kunya indicated a personal inclination or trait. According to Ibn al-Qayyim, it was a common practice in Arabia to use kunyas with names that had no relation to the individual's. In his book Tuḥfat al-mawdūd, he also gives other examples: Umar (r) was dubbed Abu Ḥafṣ, and Khaled was dubbed Abu Sulaymān but neither of them had children by those names.