Usually a variant of Ryan from Irish roots meaning little king, though it also resembles Japanese Ryon in form.
Ryon is a variant orthography of Ryan, one of the most successful Irish surnames to have crossed over into the global given-name pool. The Anglicized Ryan comes from the Gaelic surname Ó Riain, meaning "descendant of Rían." The personal name Rían itself is generally interpreted as a diminutive of "rí," the Old Irish word for "king," making the full meaning something like "little king" — a regal title worn with characteristic Irish understatement.
The Ó Riain clan was historically powerful in County Tipperary, and the name spread throughout Ireland before emigration carried it across the Atlantic. Ryan exploded as a given name in the United States from the 1960s onward, propelled partly by the actor Ryan O'Neal's visibility after the 1970 film "Love Story." By the 1990s it was a perennial top-ten name for boys.
The "y" spelling — Ryon — emerged as parents sought to individualize a name that had become almost ubiquitous, or simply to signal a slight difference in pronunciation and sensibility. The variant places gentle visual emphasis on the central vowel, giving the name a slightly more stylized appearance on paper. Today, Ryon represents the broader American tradition of personalizing inherited names through spelling variation.
It preserves all the warmth, Celtic heritage, and casual confidence of Ryan while marking its bearer as someone whose parents thought carefully about the small details. In an era of mass-produced identity, that minor orthographic deviation becomes, paradoxically, a statement of individuality.