Tune  —n. Melody. —v. (-ning) 1 put (a musical instrument) in tune. 2 a adjust (a radio etc.) To the frequency of a signal. B (foll. By in) adjust a radio receiver to the required signal. 3 adjust (an engine etc.) To run efficiently.  in (or out of) tune 1 having (or not having) the correct pitch or intonation (sings in tune). 2 (usu. Foll. By with) harmonizing (or clashing) with one's company, surroundings, etc. To the tune of colloq. To the considerable sum of. Tuned in (often foll. By to) colloq. Acquainted; in rapport; up to date. Tune up 1 bring one's instrument to the proper pitch. 2 bring to the most efficient condition. [var. Of *tone]