Short form of Kazimir (Slavic, peace-proclaimer) or Japanese names beginning with Kaz-.
Kaz functions primarily as a standalone given name and as a short form of longer Slavic names — most notably the Polish Kazimierz and Czech Kazimír, both derived from the Old Slavic elements kaziti (to destroy or announce) and mir (peace or world). The compound has been variously interpreted as 'destroyer of peace' or, in a more ceremonial reading, 'proclaimer of peace,' reflecting the ambiguity inherent in many ancient compound names. Polish kings named Kazimierz helped cement the name's prestige; Casimir the Great, who ruled Poland in the 14th century, is remembered as one of the country's wisest and most reforming monarchs.
The Anglicized form Casimir carried the name westward, and Saint Casimir of Poland — a 15th-century royal prince who rejected political power in favor of religious devotion — became a patron saint of Poland and Lithuania, spreading the name into Catholic communities across Europe. Kaz, the clipped form, emerged as a nickname in English-speaking countries for Kazimierz immigrants and their descendants, eventually gaining independence as a given name in its own right. In contemporary culture, Kaz has shed most of its Slavic formality and reads as a cool, modern moniker with strong phonetic energy — that initial hard consonant followed by a single open vowel gives it snap and clarity.
It appears in fantasy literature and gaming culture, where its brevity suits heroic characters. As a given name in the English-speaking world, it trends gender-neutral, appealing to parents who want something short, punchy, and international without being opaque.