Project - The entire automation solution (the folder with project.json). When describing the overall business value or the deployed package. For example “I just published the HR Onboarding project to Orchestrator.”
Workflow - A single .xaml file. When describing a specific technical component or a modular piece of code. For example “The ‘CalculateTax’ workflow is throwing an error.”
We also use term Process which is the business logic being automated. When talking to business users (often used interchangeably with Project). “This process handles 500 invoices a day.”