• CCVMs – config coded value maps
• Clark Kent or just Clark – the report service (it's the mild-mannered reporter)
• Fieldmapper (the IDL)
  • See birds_eye_view for an old but useful outline of the most common Fieldmapper classes
  • See reporting_data_dictionary for a more complete and up to date list of classes
• OILS – OpenILS
• OpenSRF – see opensrf
• Threadtrace – See: Working with EG Logs
• Vandelay – the MARC Import/Export module. ("Vandelay" as a short form of "Import and/or Export" comes from a Seinfeld joke.)

See abbreviations for common abbreviations you'll see around the community.