Oracle E-business Suite is a software package that lets an organization manage the key business processes. The better way to understand it is to imagine the world without it.
Automation is the key. Companies tend to automate processes to save time, money and other resources. Usually in a world without Oracle EBS or any other ERP software for that matter, there will be department specific applications where every department would have built its own application using some technology. So in one organization there would have been tens of different applications quite possibly built in different platforms. And there is also possibility that all those applications may store same data independently thus resulting in data duplication. For example the employee information is something that most departments in an organization need. Now here is a software package, mind you one software package that does this all. That removes all those applications numbered in tens and storing same data independently without any integration. And even if there is an effort of integration which is a must have for any company that will be cumbersome. And managing all those applications with proper integration can be a nightmare with heavy budget.
Oracle EBS does this all. Manages all parts of business processes, stores data only once and makes it available to all other applications with an integration that stands out. But it is software package not just single software which it looks and behaves like. There are many applications (GL, AP, Absence, Expense etc) that are bundled into product families (Financials, HRMS, CRM etc). And this fact adds more beauty to it. This modular nature of EBS allows you to implement parts of EBS rather than whole package at once. For example it is perfectly OK if you just want to implement Financials and nothing else. And as business and need grows you can add more product families to it without any hassle and without worrying about integration issues between existing and newly implemented modules.