RICEF stands for Reports, Interfaces, Conversions, Enhancements, Forms.
R - Reports
R refers report programming. Of course, firstly classical report programming, WRITE statement; then it means ALV programming with either ALV function modules or ABAP objects.
I - Interfaces
Interfaces are ALE / IDOC developments. Not only development, ABAP programming for IDOCs, also IDOC customization, management. I think it might refers EDI too.
C - Conversion
I think conversions means BDC programming, batch input function modules, BDCDATA structure, CALL TRANSACTION. Maybe conversion specifically refers conversion programs for standard batch input programs. Even we can say it refers LSMW.
E - Enhancements
Enhancements are user-exits and the object oriented model of user-exits that is BADIs.
F - Forms
Forms are SAPscript forms, SAPscript print programs, and SmartForms.
Generally its said as FRICE
F - Forms (Output) - These includes Scripts and Smart Forms
R - Reports - This includes classical and interactive reporting
I - Interfaces with other SAP and Third Party Tools - This is about ALE/iDOCs
C - Conversion - This includes BDC's and LSMW's used.
E - Enhancement - This includes User-Exits and BADIs
also check this link