Well, the word "born" in Jn 3:3 is "beget" (gennao), and it is used both of the physical and
the spiritual (1Co 4:5; Phm 10; 1Jn 2:29, 3:9, 4:7, 5:1, 4, 18; Jn 3:3, 5-6, 7, 8).
And "again" in Jn 3:3, 7 is anothen, which means "anew; from above."
So "born anew, from above" (Jn 3:3, 7) is spiritual rebirth.
The key thing to realize is 'from above'. There is a message in the verse.