f/abbr. f-stopAmerican Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.F, f (?f) n., pl. Fs F’s, fs f’s. 1. the sixth letter of the English alphabet, a consonant. 2. any spoken sound represented by this letter. 3. something shaped like an F. 4. a written or printed representation of the letter F or f. F 1. female. 2. Genetics. filial. 3. firm. 4. franc. 5. French. F Symbol. 1. the sixth in order or in a series. 2. (sometimes l.c.) (in some grading systems) a grade or mark that indicates academic work of the lowest quality; failure. 3. a. the fourth note of the ascending C major scale. b. a tonality having F as the tonic. 4. Math. a. field. b. function (of). 5. Fahrenheit. 6. farad. 7. fluorine. 8. (sometimes l.c.) Physics. a. force. b. frequency. c. fermi. 9. phenylalanine. f 1. firm. 2. Music. forte. f Symbol. 1. focal length. 2. fluid dram. 3. Math. function (of). F. 1. Fahrenheit. 2. February. 3. Fellow. 4. forint. 5. franc. 6. France. 7. French. 8. Friday. f. 1. farad. 2. farthing. 3. father. 4. fathom. 5. feet. 6. female. 7. feminine. 8. filly. 9. fine. 10. folio. 11. following. 12. foot. 13. form. 14. formed of. 15. franc. 16. from. f/ Symbol. f-number. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.