coinciding

Coinciding is the present participle of coincide, describing something that occurs at the same time or occupies the same position, or that shares matching characteristics. The term derives from Latin coincidere, from com- (together) and incidere (to fall upon).

In geometry and mathematics, two objects are said to coincide when they occupy the same location in space. Two lines coincide if they lie on top of each other and are the same line; two points coincide if they are identical; two sets coincide if they have exactly the same elements. Coincidence of objects can be exact or up to a chosen coordinate system, such as when transforming a figure by translation or rotation.

In everyday use, coinciding events are events that happen at the same time. Examples include clocks that show the same time, schedules that align, or anniversaries that fall on a holiday. The notion also appears in astronomy, where celestial events may coincide, such as a solar eclipse occurring near a planetary alignment.

In statistics and probability, coincidence refers to the appearance of a relationship or pattern that may arise by chance rather than causation. People often interpret coincidences as meaningful connections, but statistical reasoning and the context of data are required to assess whether a coincidence is surprising or expected under a given model.

Common related terms include coincidence, coincide, and coincident; they are used across disciplines to denote alignment in time, space, or attributes.