Hmmm...
Sphereoid is a technical term and it does not mean 'a bit like a sphere'. It means the surface obtained by rotating an ellipse. Sphereoids don't have one pointy end and one round end (although they can have two pointy ends like a rugby ball). They are a special case of ellipsoid.
Ellipsoids in general cannot be obtained by rotating any 2-dimensional curve: think of a rugby ball that has been sat on, or an orange squeezed at the sides.
That just leaves ovoid, which is an adjective meaning 'egg-shaped'. However, this can refer to both a 2-dimensional or 3-dimensional egg shape.
Sorry to be so pedantic, and for year 1 all this is way over the top, but ellipsoid and spheroid are simply wrong. If the teacher says something different send them round here for an argument .