Dejanira is a female given name of Greek origin, derived from the mythological Δεϊάνειρα (Deianēra), the legendary wife of Heracles whose name stems from δεινός (deinos), meaning “mighty” or “man-destroyer.” In the United States its frequency has been modest—peaking at 36 newborns in 1995 and otherwise hovering in single digits—resulting in Social Security rankings in the mid-800s and keeping it off most naming radar screens. English pronunciation converges to dey-JUH-NEER-uh in both American and British usage, simplifying adoption across dialects. Beyond its classical pedigree, Dejanira also appears in taxonomic literature as a genus within the Sparassidae spider family, offering a technical dimension that may appeal to scientifically inclined parents. By combining mythic resonance with low prevalence and specialized associations, Dejanira provides a distinctive option for families seeking depth and originality over ubiquity.