A subcontractor is someone hired by the main contractor to do a specific part of a larger job. When a company wins a contract to build a school, they become the general contractor responsible for the whole project. But they can't do everything themselves: they need electricians to wire the building, plumbers to install pipes, and carpenters to build cabinets. Each of these specialists is a subcontractor, brought in to handle their particular expertise.

The general contractor manages the overall project, coordinates the schedule, and makes sure all the pieces fit together. The subcontractors focus on their specialized tasks. A roofing subcontractor installs the roof. A painting subcontractor handles the painting. Each subcontractor has a contract with the general contractor, not with the school district that ordered the building.

You see this arrangement in many fields beyond construction. A movie studio might hire a main production company, which then brings in subcontractors for special effects, music, or catering. A company organizing a big event might subcontract the photography, sound system, and food service to different specialists. This system lets the main contractor take on complex projects while relying on experts for each component. The subcontractor gets paid for their specific work, while the general contractor ensures everything comes together on time and within budget.