Person
Irad עִירָד
third generation from Adam in the line of Cain
"And to Chanoch was born Irad, and Irad begot Mechuyael" (Bereshit 4:18).
One line for a whole generation. The Torah passes through Cain's genealogy quickly—names, and on—while Seth's line is given a whole chapter with each man's years.
No conclusion about the men themselves follows from that brevity: the Torah tells at length what its reckoning of years requires, and the reckoning runs through Seth, from whom Noach came.
On the timeline
Related
Sources
Tanakh
- Bereshit 4:17–24 — the line of Cain: seven generations and Lemech's four children
Chazal: Mishnah, Talmud, midrash, Zohar
- Bereshit Rabbah 23 — the exposition of the verses on the house of Lemech: on Adah and Zillah, on Naamah, and on the crafts of Jabal, Jubal and Tubal-Cain
Basis: stated in the Tanakh.