central component
nounUK /ˈsɛntrəl kəmˈpəʊnənt/
US /ˈsɛntrəl kəmˈpoʊnənt/
The most important part that makes something work.
The engine is the central component of a car.
OTHER MEANINGS
2. A piece in the middle of a machine or system.
The central component of the toy robot moves its arms.
3. The part that everything else depends on.
Water is a central component of life on Earth.
4. The main idea in a plan or story.
Friendship is the central component of the story.