Fn. the 6th letter of the Roman alphabet ; Fn. the capacitance of a capacitor that has an equal and opposite charge of 1 coulomb on each plate and a voltage difference of 1 volt between the plates ; Fn. a degree on the Fahrenheit scale of temperature ; Fn. a nonmetallic univalent element belonging to the halogens ; usually a yellow irritating toxic flammable gas ; a powerful oxidizing agent ; recovered from fluorite or cryolite or fluorapatite ; F clefn. a clef that puts the F below middle C on the fourth line of a staff ; F layern. the highest region of the ionosphere (from 90 to 600 miles up) which contains the highest concentration of free electrons and is most useful for long-range radio transmission ; f numbern. the ratio of the focal length to the diameter of a (camera) lens system ; F regionn. the highest region of the ionosphere (from 90 to 600 miles up) which contains the highest concentration of free electrons and is most useful for long-range radio transmission ; F. D. Rooseveltn. 32nd President of the United States ; elected four times ; instituted New Deal to counter the Great Depression and led country during World War II (1882-1945) ; F. G. Bantingn. Canadian physiologist who discovered insulin with C. H. Best and who used it to treat diabetes(1891-1941) ; F. Scott Fitzgeraldn. United States author whose novels characterized the Jazz Age in the United States (1896-1940) ; F.I.S.C.n. a secret federal court created in 1978 by the Foreign Intelligence Surveillance Act ; responsible for authorizing wiretaps and other forms of electronic surveillance and for authorizing searches of suspected spies and terrorists by the Department of Justice or United States intelligence agencies ; fan. the syllable naming the fourth (subdominant) note of the diatonic scale in solmization ; fa lan. meaningless syllables in the refrain of a partsong ; FAAn. an agency in the Department of Transportation that is responsible for the safety of civilian aviation ;
