Irad is a name in Hebrew. In the book of Genesis, the grandson of Cain is Irad.
Genesis 4:18, in a genealogical passage about the descendants of Cain, contains the only reference to Irad in the Bible: "To Enoch was born Irad; and Irad was the father of Mehujael, and Mehujael the father of Methushael, and Methushael the father of Lamech" (New Revised Standard Version).
The lineage of Cain in Genesis 4:17-22 closely parallels the lineage of Cain's brother Seth found in Genesis 5:1-32. In terms of the Documentary hypothesis, the genealogy of Cain is attributed to the Jahwist source, while the genealogy of Seth is attributed to the Priestly source. The J list and P list contain seven pairs of similar names, and the "Irad" of the Jahwist source is parallel to the "Jared" of the Priestly source.