It is a line segment.
I believe that is the definition of a straight line.
It is the locus of points such that the sum of their distance from two distinct fixed points is a constant.
The two fixed points are the foci but these do not define the shape of the ellipse. You also need to know the eccentricity.
A line in 2D and a plane in 3D A perpendicular bisector of the line connecting the 2 given points
Two nonmoving objects that are useful reference points are a stationary pole or a fixed building. These objects can serve as points of comparison or markers to determine direction, distance, or positioning.
Reference points on Earth's surface are fixed locations used as markers for navigation, surveying, and mapping. These points can be natural, like mountain peaks or lakes, or man-made, like buoys or survey monuments. They provide a consistent framework for determining positions and distances on the Earth's surface.
The two basic points of reference on the surface of the Earth are the North Pole and the South Pole. These points represent the northernmost and southernmost points on Earth's axis of rotation, respectively.
The two basic points of reference on the surface of the Earth are the North Pole and the South Pole. These points represent the northernmost and southernmost points on the Earth's axis of rotation.
It is a line segment.
infinite
I believe that is the definition of a straight line.
It is the locus of points such that the sum of their distance from two distinct fixed points is a constant.
The Celsius scale is based on two fixed points: The freezing point of water at 0 degrees, and the boiling point of water at 100 degrees.
They are North Pole and South Pole
In Euclidian or plane geometry, there can be only one line through two fixed points. Lines cannot actually be drawn; if you see it it is not a geometric line. If the points are on a curved surface as in a geometry that is non-Euclidian, then there can be infinitely many lines connecting two points.
The two fixed points are the foci but these do not define the shape of the ellipse. You also need to know the eccentricity.