Prior to the release of Oracle R12, Treasury was part of Cash Management. The functions that you can perform in Cash Management and Treasury are similar though they are two different products in R12.
Treasury allows you to manage Cash, Investment Portfolio, and also gives you the capability to create journal entries based on inter-fund, inter-entity, and inter-bank transfers.
Oracle Treasury also enables management of interest accruals and charges. Specific configurations drive how these transactions are created. Templates allow data to be captured for reporting and manage positions for cash, funds, and portfolios.