A long ray is a one-dimensional shape made from gluing an uncountably infinite number of half-open line segments together in the order given by ω1.[1] This makes it longer than the ray, which is made from gluing a countably infinite number of half-open line segments in the order given by ω.
It can be considered as being the nonnegative part of a number line which enumerates all countable ordinals.
A long ray has a boundary comprising the single point on the closed end. If this point is removed, the open long ray can be constructed.