| PLL | Phase Locked Loop |
| DPLL | Digitally Phase Locked Loop |
| DPLL | Digital Phase-Locked Loop |
| PAL | Phase Alternating Line / Loop [TV] |
| LIS | Locked-In-Syndrom [Medizin] |
| CL | Closed Loop |
| FITL | Fiber In The Loop |
| LGR | Loop-Gap Resonator |
| RLL | Radio in the Local Loop |
| LAC | Loop Assignment Center |
| CLS | Closed-Loop Stripper |
| DLL | Digital Local Loop zweiadrige Verbindung eines ISDN-Anschlusses |
| DLC | Digital Loop Carrier |
| CCL | Closed Conference Loop |
| AL | Arbitrated Loop [engl.] IT-Netzwerk Begriff |
| MLT | Mechanized Loop Testing |
| LSS | Loop Switching System |
| LOC | Loop On-line Control |
| LIP | Loop Initialization Protocol |
| WLL | Wireless Local Loop |
| ADL | All Digital Loop [engl.] Schnelle Datenübertragung über das Telefonnetz |
| FCLC | Fibre Channel Loop Community |
| CLCC | Closed Loop Congestion Control |
| FC-AL | Fiber Channel - Arbitrated Loop |
| CLSA | Closed-Loop Stripping Analyses |
| RAP | Radio Local Loop Access Profile |
| DDLCN | Distributed Double Loop Computer Network |
| ADSL | Asymmetrical Digital Subscriber Line // Loop [engl.] Teilnehmer-Anschluss mittels Telefonkabel |
| RPELTP | Regular Pulse Excitation with Long-Term Prediction Loop |
| TPC | Three-Phase Catalysis |
| PN | Phase Noise |
| PCE | Phase Change Erasable |
| RPA | Random Phase Approximation |
| PE | Phase Encoded / Encoding |
| PCM | Phase Change Material |
| PWP | Phase Wobble Prepit |
| PSK | Phase Shift Keying |
| mpic | Mobile Phase Ion Chromatography |
| TPV | Transport en Phase Vapeur |
| bpc | Bonded-Phase Chromatography |
| LPE | Liquid Phase Epitaxy |
| DPC | Differential Phase Contrast |
| RPC | Reverse Phase Chromatography |
| DPO | Data Phase Optimization |
| D2PC | Dynamic Two Phase Commitment |
| RAMP | Ratings And Maintenance Phase |
| SCPP | Self-Consistent Phase-Phonon |
| PCR | Phase Change Recording |
| RRPA | Relativistic Random-Phase Approximation |
| RPAE | Random-Phase Approximation with Exchange |