- (Canada) Initialism of Newfoundland and Labrador, a Canadian province.
- (US, pharmacology) Initialism of National Formulary, a book of public pharmacopeial standards.
- (slang) Initialism of not frat, denoting things counter to the culture of Greek life, particularly in the Southern United States
- (US, aviation) Prefix code for NASA research fighter plane designations.
- (pathology) Initialism of necrotizing fasciitis.
- (pathology) Initialism of neurofibromatosis.
- (Unicode) Initialism of normalization form.
- Unicode Consortium, Unicode Standard Annex #15, revision 41 (2014-06-05), § 1.2, table 1: “Normalization Forms”
- USP-NF website