A component is a part of an asset that for any reason needs to be identified separately from its parent asset. Reasons may include a different useful life or maintenance regime.
Alternate Definitions
The International Infrastructure Management Manual defines components as "specific parts of an asset having independent physical of functional identity and having specific attributes such as different life expectancy, maintenance regimes. risk or criticality."
An essential part of an asset which may be separately removed and replaced to extend the life of the asset. (e.g. road seal as a component of a road asset; or a roof as a component of a building asset.) - A Wealth of Opportunities.