From the gemstone jet (a black mineral), or a diminutive of Henrietta.
Jetta derives from "jet," the lustrous black gemstone formed from fossilized driftwood, whose name came through Old French "jaiet" from Latin "gagates" and ultimately Greek "gagatēs," referring to the town of Gagai in ancient Lycia (modern Turkey) where the stone was famously mined. As a given name, Jetta carries the gemstone's associations: sleek, dark, polished, and quietly remarkable. It can also be read as a feminine elaboration of Jett, a given name popularized in the American South and West.
The name has a distinctly mid-century American feel, having appeared modestly in birth records from the 1920s through the 1960s, particularly in the Southern United States and among communities with Scandinavian heritage (where "Jetta" has been used as a given name independently). In Scandinavian contexts it may derive from a pet form of names beginning with the Germanic element "gaut." Volkswagen's popular compact car, the Jetta, introduced in 1979, gave the name an unexpectedly modern automotive echo.
Today Jetta feels like a gem waiting to be rediscovered. It has the bold, one-word energy of names like Wren or Juno, with a slightly edgier, darker undertone. For parents drawn to short, punchy names with vintage credentials and a hint of rock-and-roll cool, Jetta offers something genuinely rare: a name that sounds invented but isn't.