Enterprise systems (ES) are large-scale application software packages that support business processes, information flows, reporting, and data analytics in complex organizations. While ES are generally packaged enterprise application software (PEAS) systems they can also be bespoke, custom developed systems created to support a specific organization's needs.
Types of enterprise systems include:
- enterprise resources planning (ERP) systems ,
- enterprise planning systems , and
- customer relationship management software.
Although data warehousing or business intelligence systems are enterprise-wide packaged application software often sold by ES vendors, since they do not directly support execution of business processes, they are often excluded from the term.
From a hardware perspective, enterprise systems are the servers, storage and associated software that large businesses use as the foundation for their IT infrastructure. These systems are designed to manage large volumes of critical data. These systems are typically designed to provide high levels of transaction performance and data security. 
Vendors in this space include IBM, Oracle, HP and more.