Vendor
What it is:
A vendor is a company or person that sells goods or services.
How it works/Example:
Vendors sell accounting services, food, electricity, hair styling, maid service, toilet repair, and just about anything else imaginable.
Why it matters:
Vendors don't just sell goods and services, they also buy goods and services from other vendors. For instance, Company XYZ might be an accounting services vendor, but it also purchases office supplies from other vendors.