Costing- The technique and process of ascertaining cost.
Cost Accounting - The process of accounting for costs which begins with a recording of income and expenditure or the basis on which they are calculated and ends with the preparation of periodical statements and reports for ascertaining and controlling costs.
Cost Accountancy- The application of costing and cost accounting principles, methods and techniques to the science, arts and practice of cost control and the ascertainment of profitability.