Full definition
Third party is defined as: A third party is any external individual or organisation your business relies on but does not directly employ - suppliers, vendors, subcontractors, agents, partners, resellers and referral sources all count.
The umbrella term matters because regulators, insurers and clients apply the same expectations across the whole category. If a third party handles your data, works on your site or represents you to a customer, you carry residual risk.
Managing third parties as a single population - rather than siloed by procurement, IT and HR - is the shift TPRM programmes make.