What is the meaning of the word "Ahad" in Surat Al-Ikhlas, "Say, 'He is Allah, [who is] Ahad'," and what does it mean when used to refer to "one of the people"?

The meaning of His, the Almighty's, saying: (Say: He is Allah, the One) is the One who has no peer or similitude. The word "Ahad" (One) is not used in affirmation except for Allah Almighty, because He is perfect in all His attributes and actions. Therefore, people's saying "one of the persons" is incorrect in affirmation. As for negation, it is permissible to say: "No one came to me."