在机械工程学中，指称机器中每一个独立的运动单元体称为一个构件它可以由单个零件或数个零件构成。两个以上的构件可进一步组成运动副

此外，构件的概念被使用到计算机科学中，指一个系统或软体中的基本组成部分。

Machine element refers to an elementary component of a machine. These elements consist of three basic types:

While generally not considered to be a machine element, the shape, texture and color of covers are an important part of a machine that provide a styling and operational interface between the mechanical components of a machine and its users.