A closed curve, the locus of a point such that the sum of the distances from that point to two other fixed points (called the foci of the ellipse) is constant; equivalently, the conic section that is the intersection of a cone with a plane that does not intersect the base of the cone.
A mark consisting of (in English) three periods, historically or more formally with spaces in between, before, and after them β . . . β, or more recently a single character ββ¦β Ellipses are used to indicate that words have been omitted in a text or that they are missing or illegible.