Feminine variant of Dana or Dane, meaning 'from Denmark' or 'God is my judge.'
Dayna is a phonetic respelling of Dana, a name with multiple competing etymological paths. The most commonly cited is the Old English and Old Norse Dane, referring to someone from Denmark, which would make it a nationality-based name in the tradition of Frank or Norman.
However, Dana also exists as a Hebrew name meaning judge, and in Irish mythology, Danu — sometimes rendered Dana — is the great mother goddess of the Tuatha Dé Danann, the divine race who inhabited Ireland before the arrival of the Gaels, lending the name deep mythological roots in Celtic tradition. Dana entered widespread use as a given name for both boys and girls in the United States during the twentieth century, with the feminine spelling Dayna emerging as a stylistic variant in the mid-century decades when respelled names became fashionable. The Dana/Dayna cluster was particularly popular in the 1960s through 1980s, carried in part by cultural figures like actress Dana Andrews, dancer and actress Dana Wynter, and eventually the musician Dana, who represented Ireland in the 1970 Eurovision Song Contest with the sweetly memorable All Kinds of Everything.
The spelling Dayna gives the name a slightly more individualized feel, signaling a feminine identity more immediately than the traditionally gender-neutral Dana. Today Dayna sits in the comfortable territory of retro-revival — a name parents might choose to honor a grandmother's generation while still feeling genuinely wearable for a child born in any recent decade.