All 3 Uses

component
in
The Hitchhiker's Guide to the Galaxy
(Auto-generated)

The reason why it was published in the form of a micro sub meson electronic component is that if it were printed in normal book form, an interstellar hitchhiker would require several inconveniently large buildings to carry it around in.†
Chpt 3
Further circuits amused themselves by analyzing the molecular components of the door, and of the humanoids' brain cells.†
Chpt 11
For years radios had been operated by means of pressing buttons and turning dials; then as the technology became more sophisticated the controls were made touch-sensitive—you merely had to brush the panels with your fingers; now all you had to do was wave your hand in the general direction of the components and hope.
Chpt 12 *

components = parts (in this case, of the radio)

Definitions:

(1) (component)
a self-contained part of something that when combined with other parts makes something that is larger or more complex
(2) (meaning too rare to warrant focus)
A comprehensive dictionary will also describe more specialized senses of component.