The name reached its all-time peak in 1996 with 3 births ranking #3795. STABLE Recent data shows the name is currently stable.
Kian has more than one genuine route. Behind the Name gives it both a Persian entry meaning "king, foundation, symbol of pride" and a modern English entry as a variant of Cian.
Because both routes are current and well attested, Kian is better described as a multi-origin name than forced into one single explanation. In English-speaking use, the modern Cian-linked spelling and the Persian name both seem relevant.