Component, n.
A constituent part; an ingredient. Component of force (Mech.), a force which, acting conjointly with one or more forces, produces the effect of a single force or resultant; one of a number of forces into which a single force may be resolved.
1 other Webster entry under this spelling
Component, a.
Serving, or helping, to form; composing; constituting; constituent. The component parts of natural bodies. Sir I. Newton.
Shades of meaning
Fernald has no entry of its own for component; he lists it under part.
Where he writes about it:
A component, constituent, ingredient, or element is a part of some compound or mixture; an element is necessary to the existence, as a component or constituent is necessary to the completeness of that which it helps to compose; an ingredient may be foreign or accidental. — from part