Gliedn(a component of two or more lens elements which makes up a part of a complete optical system; also applied to separate uncemented lenses used on their own in an optical system)
A general term that is used to mean one part of something more complex(For example, a computer system may be a component of an IT service, or an application may be a component of a release unit. Components are co-operating packages of executable software that make their services available through defined interfaces. Components used in developing systems may be commercial off-the-shelf software (COTS) or may be purposely built. However, the goal of component-based development is to ultimately use as many pre-developed, pretested components as possible)