What term describes Jupiter's flattened shape caused by rapid rotation?

Jupiter’s flattened shape caused by rapid rotation is called an oblate spheroid.

Jupiter spins once in roughly 10 hours, the fastest rotation of any planet in the Solar System. That rapid spin produces centrifugal effects that push material outward around the equator, making the equatorial radius about 7% larger than the polar radius.

“Oblate” means flattened at the poles, while “spheroid” indicates a shape broadly like a sphere. Jupiter is not a perfect sphere, but neither is it a triaxial ellipsoid: its dominant distortion is the equatorial bulge caused by rotation. A prolate spheroid would instead be stretched toward its poles.

The effect is large enough to be detected with amateur telescopes, although Jupiter’s cloud bands and storms can make its outline appear more complex. Because Jupiter is a fluid gas giant, different atmospheric latitudes also rotate at slightly different speeds, a phenomenon called differential rotation.