A "long line" refers to a queue or series of people or objects arranged in a straight formation, extending over a considerable distance. This can occur in various settings, such as at a store checkout, a ticket counter, or during events where people wait for entry. Long lines often indicate high demand for a service or product. In mathematics, a "long line" can also describe a specific type of topological space. It is an example of a space that is not compact and has unique properties, often used in advanced studies of topology and mathematics.