/ Dictionary / Index F fine structure: Meaning and Definition of Find definitions for: fine' struc'ture Pronunciation: (fīn), [key] — Physics. Physics. a group of lines that are observed in the spectra of certain elements, as hydrogen, and that are caused by various couplings of the azimuthal quantum number and the angular momentum quantum number. Cf. hyperfine structure. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. finestra fine-tooth comb Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language