From Wikipedia..."Business analysis is a research discipline of identifying business needs and determining solutions to business problems. Solutions often include a software-systems development component, but may also consist of process improvement, organizational change or strategic planning and policy development."

From Ross...Business process analysis involves documentation of existing processes to describe work flows and requirements and analysis to identify improvements and process interface opportunities. Process analysis is an important component of system implementations and integrations.

System implementations involve documentation of existing processes and analysis of how well existing process practices fill the requirments of the process used in the system being implemented. Gaps in data requirements or proceedure are identified and process modifications devised to close the gaps.

System integrations involve analysis of the products and requirements of the systems being integrated. Generally some sort of communication between the systems is required either in the form of access to API's provided the by the system creators or data transfers that can be picked up and used by the processes in the recipient system.