People begin to call on Yahweh's name
In the days of Seth's son Enosh, people began to worship God publicly by name.
A son was also born to Seth, and he named him Enosh. At that time men began to call on Yahweh’s name.
Genesis 4:26 (World English Bible)
While Cain's line was building cities and boasting of revenge (Genesis 4:17–24), Seth's line is marked by worship. Genesis notes that in Enosh's time people began to call on Yahweh's name, which most take to mean public prayer and worship.
Dating notes
Tied to Enosh's birth (3769 BC). The verse may describe the years following his birth rather than the year itself.