| ACNA | Access Customer Name Abbreviation |
| AOCN | Administrative Operating Company Number. The term "AOCN" also refers to the company that updates rating and routing information associated with central office code assignments. |
| ANI | Automatic Number Identification |
| ANSI | American National Standards Institute |
| ATIS | Alliance for Telecommunications Industry Solutions (www.atis.org) |
| BIRRDS | Business Integrated Routing and Rating System |
| CIC | Carrier Identification Code |
| CIGRR | Common Interest Group on Rating and Routing |
| CLEC | Competitive Local Exchange Carrier |
| CLLI™ | COMMON LANGUAGE® Location Identification |
| CLONES™ | Central Location ON-line Entry System |
| CO | Central Office |
| COCAG | Central Office Code Assignment Guidelines |
| EN | Emergency Notification |
| ERC | Easily recognizable (area) code |
| FCC | Federal Communications Commission |
| FG A,B,C,D | Feature Group A, B, C, D |
| FNPA | Foreign NPA |
| HNPA | Home NPA |
| ILEC | Incumbent Local Exchange Carrier |
| INC | Industry Numbering Committee |
| IXC | Interexchange Carrier |
| LATA | Local Access and Transport Area |
| LEC | Local Exchange Carrier |
| LIDB | Line Information Data Base |
| LNP | Local Number Portability |
| LRN | Location Routing Number |
| MSA | Metropolitan Statistical Area |
| MTE | Months to Exhaust |
| MTSO | Mobile Telephone Switching Office |
| NANC | North American Numbering Council |
| NANP | North American Numbering Plan |
| NANPA | North American Numbering Plan Administration |
| NARUC | National Association of Regulatory Utility Commissions |
| NASC | Number Administration Service Center (Toll-Free 800/866/877/888 database) |
| NIIF | Network Interconnection and Interoperability Forum |
| NNACL | NPA/NXX Active Code List |
| NNAG | NPA/NXX Activity Guide |
| NOWG | Number Oversight Working Group, a subgroup of the NANC |
| NPA | Numbering Plan Area (Area Code) |
| NPAC | Number Portability Administration Center |
| NRO | Number Resource Optimization |
| NRRIC | Network Rating and Routing Information Committee |
| NRUF | Numbering Resource Utilization Forecast |
| NXX | The format of an NPA code or a central office code (N=2-9, X=0-9) |
| OBF | Ordering and Billing Forum |
| OCN | Operating Company Number |
| PA | Pooling Administrator |
| PCS | Personal Communications Service |
| PSAP | Public Safety Answering Point |
| PSC | Public Service Commission |
| PSTN | Public Switched Telephone Network |
| PUC | Public Utilities Commission |
| RA | Rate Area |
| RC | Rate Center |
| RCC | Rate Center Consolidation |
| SAC | Service Access Code |
| SP | Service Provider |
| STP | Signaling Transfer Point |
| TN | Telephone Number |
| TPM™ | Terminating Point Master |
| TRA | TELCORDIA™ Routing Administration |
| V&H | Vertical & Horizontal (Coordinates) |
| VSC | Vertical Service Code |