Usually a short form of Reza, from Persian and Arabic usage meaning "contentment" or divine favor.
Rez has roots that stretch across two great civilizations. In Persian and Arabic tradition, it derives from 'Reza' (رضا), meaning contentment, satisfaction, or divine approval — a name of profound spiritual significance in the Islamic world. Ali ibn Musa al-Ridha, the eighth Imam of Twelver Shia Islam, bore this name and is venerated at the magnificent shrine in Mashhad, Iran, one of the most visited pilgrimage sites on Earth.
Reza was also the given name of Reza Shah Pahlavi, the founder of Iran's Pahlavi dynasty, making it a name associated with both sacred devotion and worldly authority. Separately, Rez connects to the Hungarian 'Rezső,' the Magyar rendering of Rudolf, from the Old High German 'Hrodulf' — 'fame' and 'wolf' combined into a name of fierce nobility. It also carries echoes of the Latin 'rex,' meaning king, a word that permeated European naming culture through the medieval period and lives on in names like Rex and Reginald.
As a standalone name, Rez has gained traction in the 21st century as parents worldwide embrace short, punchy, complete names that need no nickname. It has a modernist economy to it — one syllable, three letters — while carrying the full weight of its Persian spiritual heritage and its royal European associations. The name appears in contemporary fiction and music, lending it a cool, cross-cultural currency that spans generations.