pinhole

A pinhole is an extremely small hole, often one that looks as if it were made by a pin. You might notice one in paper, cloth, metal, or plastic. Sometimes it is only big enough to let a little light, air, or water pass through.

The word is also common in photography. A pinhole camera uses a very small opening instead of a lens to form an image. In everyday language, people also talk about a pinhole leak, meaning a tiny leak that may seem small but can still cause trouble over time.

Imagine holding up a sheet of paper and making the smallest possible hole with a needle. That tiny opening is a pinhole. It is so small that you may only notice it when light shines through it or when air or water slowly escapes through it.

The word is often used for very small holes in thin materials or surfaces. You might read about pinholes in paper, fabric, plastic, rubber, paint, or metal. In many cases, the hole is unwanted and is treated as a flaw because even a tiny opening can matter.

One common use appears in photography. A pinhole camera does not use a lens. Instead, light passes through a very small hole and forms an image on film or on a digital sensor. This is one of the clearest and most familiar uses of the word.

The term also appears in phrases like "pinhole leak." This means a leak caused by a hole so small that it can be hard to find at first. A pipe, tire, or container may have a pinhole leak that starts as a small problem but becomes more serious later.

Overall, a pinhole is simply a very tiny hole, especially one that lets a small amount of light, air, or liquid pass through. The idea is not just size, but also the way such a tiny opening can still have a clear effect.