On-premises (often abbreviated as "on-prem") refers to a software deployment model in which applications and data are hosted on physical servers and infrastructure within an organization, as opposed to models based on external cloud servers. This model allows companies to retain full control and responsibility over their IT resources.
Important aspects of on-premises:
Importance for companies: On-premises is particularly attractive for companies that have high security, compliance and data sovereignty requirements or need specific customizations that are more difficult to implement in a cloud environment. It also offers precise cost control by avoiding recurring subscription fees.