What is Definition of training center in business?

This answer depends on the specific entity to which it is being referred but generally a business training center falls under one of two categories.
The first is that of an academic training center that provides a structured learning environment to acquire the skills necessary to perform in the business world. Skills taught can include computer hardware and software, accounting, administrative and secretarial skills, management skills and so on. This type of training center can be located either in an institute of academia such as a college or trade school, or it can be located in-house within a company to train their employees

The second type could be a business training and development center. These are for small business owners and aspiring entrepreneurs who desire to start, grow or develop their own business. The focus here is on management and operations. These types of facilities offer resources to assist entrepreneurs with their business planning and development, market research and other operational needs. SCOPE and the SBA are examples of possible business training centers.