Why was he called Adam? What is the linguistic origin of this name?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. He was named so because he was created from the earth's surface (adīm). [Ibn ʿAbbās, Ibn Jubayr, al-Zajjāj]
2. He was named so because of his reddish-brown complexion (udmah). [Al-Ḍaḥḥāk, al-Nadr ibn Shumayl, Quṭrub]