- Not Elsewhere Classified, a phrase used in classification codes such as Standard Industrial Classification, International Standard Classification of Occupations, DSM-IV-TR, DSM-5, ICD-9, and ICD-10.
- National Exhibition Centre. The largest exhibition space in the United Kingdom.
- National Executive Committee (of a political party).
- Nippon Electric Company, Ltd. (renamed to NEC in 1983.) Electronics manufacturer.
- National Electrical Code: its purpose is the practical safeguarding of persons and property from hazards arising from the use of electricity.