Ulyana is the Ukrainian, Belarusian, and Russian form of Juliana, which ultimately derives from the Roman family name Iulianus. Its root may be the Greek word ioulos (downy-bearded), or it could be related to Jupiter (Iuppiter in Latin). Jupiter comes from the Indo–European root *Dyew-pater; Dyews means Zeus, and pater is father. In turn, Zeus derives from root *dyew- (“sky” or “shine”).
Uilyam is the Ukrainian form of William, which comes from the Germanic name Willahelm (will helmet).