Synonyms for Prolate (same or very similar meaning)
WordNet sense 1 (having the polar diameter greater than the equatorial diameter):
watermelon-shaped
WordNet sense 2 (rounded like an egg):
elliptic, elliptical, oval, ovate, ovoid, egg-shaped, oviform, oval-shaped
WordNet sense 3 (curving and somewhat round in shape rather than jagged):
rounded
From the ODE community, based on WordNet
add/edit