Usually a short form of Dexter, from Latin meaning right-handed or skillful.
Dex began its life as a crisp shortening of Dexter, itself drawn from the Latin word dexter meaning "right-handed" or "skillful" — a term the Romans used both literally and as a compliment to someone of dexterity and competence. The Latin root traveled through Old French and into English, where it carried connotations of cleverness and adroitness long before it became a proper name. As a standalone given name, Dex owes much of its cultural footprint to popular media.
The Showtime series Dexter (2006–2013) brought the name into millions of households, associating it with a razor-sharp, methodical protagonist — lending Dex an edgy, cerebral quality that parents found surprisingly appealing. Earlier, the eccentric boy-genius Dexter from the Cartoon Network animated series Dexter's Laboratory made the name feel inventive and precocious for a generation of millennials. Today Dex operates as both a nickname and a given name in its own right.
Its appeal lies in its punchy one-syllable energy — modern parents seeking something short and strong without feeling trendy often land here. It sits comfortably in the same register as Rex, Jax, and Hex, while carrying slightly more historical grounding. Dex has particular resonance in tech and creative communities, where the associations of skill and dexterity feel very much at home.