annular

Annular is a term used across various scientific and technical disciplines to describe a shape or structure characterized by a ring or circular form with a central opening. The word derives from the Latin "annulus," meaning "little ring."

In geometry, an annular shape refers to a ring-shaped region bounded by two concentric circles or ellipses. This shape is commonly visualized as a disk with a hole in the middle, such as a doughnut or washer. The area of an annulus can be calculated by subtracting the area of the smaller inner circle from that of the outer circle.

In astronomy, the term "annular" is associated with the Annular Solar Eclipse, which occurs when the Moon passes in front of the Sun but appears smaller than the Sun in the sky. This results in a ring-like appearance called a "ring eclipse" or "annulus," where the Sun's outer edges are visible around the Moon's silhouette.

In engineering and manufacturing, annular components are often used in seals, gaskets, and washers to provide a ring-shaped interface or support structure. Such components are valued for their ability to distribute forces evenly and fit within circular housings.

The concept of annularity is also used in geology and biology to describe ring-shaped or hollow features, such as annular faults or structures with a circular symmetry.

Overall, the term "annular" describes a shape or structure that is ring-like, with applications spanning multiple fields including mathematics, astronomy, engineering, geology, and biology. It emphasizes symmetry, central openness, and circularity in various contexts.