A cylinder (Latin cylindrus = to roll) is a geometric body defined as a surface whose points have the same distance from a fixed straight line, an axis. In this ideal case, the cylinder will have an infinite length. In application, however, most cylinders are bounded by their bases, which terminate the cylinder's lateral surface at both ends. In engineering, the cylinder is an important term for machine elements and assemblies. These are similar in terms of their cylindrical shape. The cylindricity of components can be toleranced quite easily as a shape specification thanks to the standards relating to shape and position tolerances: For example, the cylindricity of a toleranced cylindrical surface is considered toleranced if it lies between two coaxial cylinders. In technical drawings, the cylindricity tolerance, like all other form and position tolerances, is entered with the symbols and annotations according to the rules of applicable standards.