🔼The name Cainan in the Bible
The occurrence of the name Cainan in Luke 3:36 and 3:37 as the son of Arpachshad is a bit of a mystery, albeit a contested one. The original genealogy of Genesis 11:13 does not contain this Cainan but the Septuagint does. Hence critics conclude that Luke used the flawed Septuagint and copied its mistakes into his gospel.
But, note others, this Cainan fellow only occurs in later versions of the Septuagint. Older copies follow the genealogy of the Book of Genesis accurately. And it's then concluded that both the Septuagint version that Luke used and Luke's original gospel never contained Cainan the son of Arpachshad, and this name was erroneously inserted into both at later dates.
Only when archeology and Scripture Theorists were able to determine which version was the oldest, was the original discovered, but up until this present day, the gospel of Luke contains an extra Cainan.
🔼Etymology of the name Cainan
The gospel of Luke uses the same Greek spelling to write the name of Cainan the son of Arpachshad and Kenan, the son of Enosh, the son of Seth (Luke 3:37; Genesis 5:9). Both names apparently come from the root cluster קנה ,קין and קנן:
Alfred Jones (Dictionary of Old Testament Proper Names) maintains that the name Kenan is the same as Cain, and translates both with Possession. But the name Kenan is not identical to that of Cain, because it has an extra nun. Sometimes a nun is added to a verb to indicate a personification (verb + nun = guy who does the verb) but that personification is usually accomplished by means of the waw-nun combination.
Here at Abarim Publications we like to think that the names Cainan and Kenan derive from the verb קין (qin), meaning to chant a dirge (Amos 8:10). That would give both these names the meaning of Lamenter.
Alfred Jones, however, looks at the related name Kenite and feels there is a relation with the verb קנן (qinnen), meaning to make a nest. That would give our names the meaning of Nester. Perhaps to the Hebrews the crying of the eagle sounded like lamenting, but perhaps the two have nothing to do with each other.
NOBSE Study Bible Name List reads Fixed for both Cainan and Kenan, perhaps related them to the nest-making verb, or else the acquiring/creating verb.