Literally, SaaS is an acronym for software as a service.
Like any software, SaaS products provide the user with the ability to interact with a computer and leverage its capabilities to perform the desired action.
Some examples you may be familiar with are Quickbooks to manage your accounting, Salesforce as a CRM and even Microsoft 365 for email communication.
What makes SaaS products unique is that they are centrally hosted on the cloud as opposed to locally on your computer.
This provides several advantages of traditional local software including
One other thing to know is that SaaS products can be either open source or proprietary.