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general::
Phrase(s): tune up
[for one or more musicians] to bring their instruments into tune. • You could hear the orchestra behind the curtain, tuning up. • We have to tune up before the concert., Phrase(s): tune something up
Fig. to adjust an engine to run the best and most efficiently. • You need to tune this engine up. • Please tune up this engine so it will run more economically.
McGrawhill's American Idioms And Phrasal Verbs