Calling it royal, regal, descendant of Riagan:
http://www.ourbabynamer.com/meaning-of-Regan.html
And another that says it means nobility:
http://www.cutebabyname.com/regan.html
And another calling it little ruler or little king:
http://www.huggies.co.nz/baby-names/unisex/r/regan
And another saying that it means royal, regal, and king's heir:
http://www.babynology.com/otherorigins-regan-f13.html
I guess it's hard to believe every other site out there is wrong and this site is the only one correct, even though people on this site also posted in the comments section saying it means these things.