Within Timesheet Portal, cost centres provide a mechanism for performing the following functions:
Grouping clients, projects and tasks (which allows for cost centre-based reporting)
Linking to employee home cost centres (for reporting purposes and for selection of tasks)
To enable client invoicing among multiple organisations which are part of the same group to be hosted on a single Timesheet Portal account
Cost Centre is a generic term which you may map against actual cost centres within your organisation, but is regularly used for different purposes where categorisation of entities is required so that cost centre-grouped reports can be generated.