The term "key supplier" refers to a company or individual that provides goods, services or resources to another business. In other words, it is an external provider whose products or services are essential for the smooth operation and success of a particular organization. The phrase "one's key suppliers" therefore means those companies or individuals who supply critical materials or offer vital support to a specific enterprise. These relationships can be crucial in determining the profitability, efficiency, and overall competitiveness of an organization within its industry.