patches

A patch is a piece of material that is applied to another surface to cover a hole, mend worn fabric, or decorate. The term is also used in information technology to describe an update that alters software without replacing it entirely. In both senses, patches are intended to modify the existing item to improve function, extend life, or change appearance.

Textile patches are common for repair and decoration. They can be sewn on, ironed on, or affixed with adhesive backing. Patches range from simple repair patches used on jeans to embroidered emblems and decorative designs that identify brands, teams, or affiliations.

Software patches fix bugs, close security vulnerabilities, or add features. They are usually distributed as patch files or update packages and are installed to replace or modify existing code. Patch management is the process of identifying, testing, validating, and deploying patches while minimizing disruption and compatibility issues.

Medical patches are transdermal delivery systems applied to the skin. They release medications, hormones, or chemicals over time, providing steady dosing for conditions such as nicotine dependence or chronic pain. Skin reactions and irritation can limit use, and patch placement and timing are important for effectiveness.

Other uses include geographic patches or patch tests in medical diagnostics. The word originates from a fragment of fabric placed over a damaged area, and the concept has spread to digital and nonfabric contexts.