elliptic

As a noun initialism

is a term formed from the initial letter or letters of several words or parts of words, but which is itself pronounced letter by letter.

As an adjective elliptic is

elliptical.

As adjectives the difference between elliptic and undefined

is that elliptic is elliptical while undefined is lacking a definition or value.

As a noun oval

is oval.

As an adjective elliptic is

elliptical.

As an adjective elliptic

is elliptical.

As a noun ecliptic is

the apparent path of the Sun in the sky. More accurately, it is the intersection of the celestial sphere with the plane of the ecliptic, which is the geometric plane containing the mean orbit of the Earth around the Sun. So named because an eclipse can occur only when the Moon lies on this plane.

As a noun taxonomy

is the science or the technique used to make a classification.

As an adjective elliptic is

elliptical.

As an adjective elliptic

is elliptical.

As a proper noun nibiru is

a supposed planet in a highly elliptic orbit around the sun.

As adjectives the difference between elliptic and semistable

is that elliptic is elliptical while semistable is describing a form of elliptic curve having congruent roots.

As adjectives the difference between elliptic and hyperelliptic

is that elliptic is elliptical while hyperelliptic is (mathematics) describing an extension of elliptic functions to complex numbers.