Blue-Collar Workers: These are workers who do manual labor jobs, often involving physical skills and effort. They're like the pistons in our car engine analogy - they do a lot of heavy lifting.
Proletariat: This is a term used in Marxist theory to describe the class of wage-earning workers who don't own any means of production (like factories or land). They're similar to the fuel in our car engine - they power production but don't control it.
Labor Unions: These are organizations formed by workers to protect their rights and interests. In our car analogy, they'd be like a mechanic ensuring that all parts (workers) are treated fairly and function well together.