| Subject | English | Thesaurus |
| mil., abbr. | Autosevocom Life Cycle Extension Program | ALCEP |
| mil., abbr. | Civil Defense University Extension Program | CDUEP |
| mil., abbr. | Cobra Fleet Life Extension Program | C-FLEX |
| abbr., IT | Common filename extension | 000 |
| abbr. | external extension number | external ext number (ssn) |
| abbr., comp., net. | LAN Resource Extension and Services | LANRES |
| abbr., tech. | Life Extension Services | LES (Yuriy Melnikov) |
| comp., MS | Multipurpose Internet Mail Extension Hypertext Markup Language | Microsoft Exchange Unified Messaging Service (A standard method for sending an HTML document encapsulated with inline graphics, applets, linked documents, and other items referred to in the HTML document) |
| abbr., comp., net. | Multipurpose Internet Main Extensions Object Security Services | MOSS |
| univer., abbr. | Optometric Extension Program Foundation | OEP |
| univer., abbr. | Optometry Extension Program | OEP |
| abbr., scottish | Service Life Extension/Enhancement Program | SLEP (USA) |
| IT, abbr. | Set Normal Response Mode Extension | SNRME (SNRME) |
| abbr., scottish | Ship Life Extension Programme | SLEP (UK) |
| IT, abbr. | WOSA eXtensions for Financial Services | WOSAXFS (WOSA, MS) |
| IT, abbr. | WOSA eXtensions for Financial Services | WOSA X FS (WOSA, MS) |
