Budgeted Cost of Work Performed

This term is defined in the 3rd and the 4th edition of the PMBOK.

Budgeted Cost of Work Scheduled
See planned value (PV). This term is defined in the 3rd and the 4th edition of the PMBOK.
Actual Cost of Work Performed (ACWP)
See actual cost (AC). This term is defined in the 3rd and the 4th edition of the PMBOK.
Actual Cost
The actual cost of a project represents the true total and final costs accrued during the process of completing all work during the pre-determined period of time allocated for all schedule activities as well as for all work breakdown structured components. Actual costs are primarily made up of a number of specific items including, but [...]
Cost Variance (CV)
The term cost variance, also known by the abbreviation of CV, refers specifically to the true measurement of cost performance on a particular project. The cost variance represents the algebraic difference between the earned value of a project (also known by the abbreviation of EV), and the actual cost of the project (also known by [...]
Cost Performance Index
The cost performance index, also referred to by the abbreviation (CPI), refers specifically to a method, chart, or other instrument that is implemented for the purposes of determining/measuring the actual cost efficiency of a project. The cost performance index is determined by measuring the ratio of earned value (also known by the abbreviation of EV) [...]