Internal Logical File (ILF): An internal logical file (ILF) is a user identifiable group of logically related data or control information maintained within the boundary of the application. The primary intent of an ILF is to hold data maintained through one or more elementary processes of the application being counted.

External Interface File (EIF): An external interface file (EIF) is a user identifiable group of logically related data or control information referenced by the application, but maintained within the boundary of another application. The primary intent of an EIF is to hold data referenced through one or more elementary processes within the boundary of the application counted. This means an EIF counted for an application must be in an ILF in another application.

Data Element Type (DET): A data element type (DET) is a unique, user-recognizable, non-repeated field.

Record Element Type (RET): A record element type (RET) is a user-recognizable subgroup of data elements within an ILF or EIF.

File Type Referenced (FTR): FTR's are the combined number of Internal Logical Files (ILF's) referenced or updated and External Interface Files referenced

External Input (EI): An external input (EI) is an elementary process that processes data or control information that comes from outside the application’s boundary. the primary intent of an EI is to maintain one or more ILFs and/or to alter the behavior of the system.

External Output (EO): An external output (EO) is an elementary process that sends data or control information outside the application’s boundary. the primary intent of an external output is to present information to a user through processing logic other than or in addition to the retrieval of data or control information. The processing logic must contain at least one mathematical formula or calculation, or create derived data. An external output may also maintain one or more ILFs and/or alter the behavior of the system.”

External Inquiry (EQ): An external inquiry (EQ) is an elementary process that sends data or control information outside the application boundary. The primary intent of an external inquiry is to present information to a user through the retrieval of data or control information. The processing logic contains no mathematical formula or calculation, and creates no derived data. No ILF is maintained during the processing, nor is the behavior of the system altered.

General System Characteristics (GSC): The data and transactional functions discussed in earlier chapters together represent the total business functions that are delivered through the application being counted. Truly this is the logical representation of the functionality and does not address the physical implementation of the functions in an IT environment. The FPA method of IFPUG has captured the critical implementation features of typical applications through 14 general system characteristics. These encompass almost all the major implementation complexities that can exist, and through careful evaluation of each of the GSCs, the estimator can arrive at final function point count that includes logical as well as physical implementation properties of the application being counted.

Value Adjustment Factor (VAF): Calculated ((Total Degree of Influence * 0.01) + 0.65)

Calibration Factor (CF): general buffer depending upon practical environment

Delivery Rate (DR): No. of function points a single developer will accomplish every month

Days per person month (DPM): The no. of days a person will effectively work in a month. 20 working days in a month and Microsoft generally counts 75% utilization which means around 15 working days in a month.