The two centers of an ellipse are called the foci (singular: focus). The foci are two distinct points along the major axis of the ellipse, and the sum of the distances from any point on the ellipse to these two foci is constant. Additionally, the center of the ellipse, which is the midpoint between the foci, is another important point but is distinct from the foci themselves.
An ellipse
The answer will depend on what, if anything, the line segments have to do with the ellipse.
No.
The Ellipse (officially called President's Park South) is a 52-acre park located between the White House and the Washington Monument. Properly, the Ellipse is the name of the five-furlong circumference street within the park.
Ellipse.
... is called an "ellipse"
An ellipse
Crescent. Ellipse.
The answer will depend on what, if anything, the line segments have to do with the ellipse.
It is called an ellipse.
ellipse
An ellipse.
This shape is called a lens, a biconvex shape comprising two circular arcs, joined at their endpoints. Loosely, it could be said to be an ellipse.
The scientific name for the path of a planet around the sun is an orbit. The shape of this path can be an ellipse, with the sun located at one of the foci of the ellipse.
The path of an object in orbit around another object. It's a "conical section", shaped like a circle, but "flattened" in one direction (a circle can be considered a special case of an ellipse). An ellipse has two focal points.
No. Both foci are always inside the ellipse, otherwise you don't have an ellipse.