The is a foreign language all in itself and can make it even more confusion for some - including myself.
Here's some definitions that I found online. Hope this helps
•ADIT - Alien Documentation, Identification & Telecommunications System
•AOS - Adjustment of Status
•AOS - Affidavit of Support (you have to do this after you marry)
•BCIS - Bureau of Citizenship and Immigration Services
•CPR - Conditional Permanent Resident
•CSC - California Service Center
•DOJ - Department of Justice. BCIS (INS) falls under the jurisdiction of the DOJ
•EAD - Employment Authorization Document
•FAQ - Frequently Asked Questions
•IBIS - Interagency Border Inspection System
•INA - Immigration and Nationality Act
•INS - Immigration and Naturalization Service
•IRS - Internal Revenue Service
•IVACS - Immigrant Visa Applicant Control System
•NG - Newsgroup
•NOA1 = Notice of Action 1 which you get to confirm Immigration has your visa application
•NOA2 = Notice of Action 2 you receive this when the I-129F for example has been approved
•NVC = National Visa Center
•PISS - Pre-INS Submission Syndrome
•POE - Port of Entry. Usually airport or border crossing inspection post.
•PR - Permanent Resident (Also LPR - Legal Permanent Resident)
•RFE = request for evidence
•SSA - Social Security Administration
•SSN - Social Security Number
•TPS - Temporary Protected Status
•USC = US Citizen
•USCIS - US Citizenship and Immigration Services
•VWPP - Visa Waiver Pilot Program
ftp://http://www.visajourney.com/faq/k1faq.htm#appendix