Pronunciation: /ɪmprəvʌɪˈzeɪʃn/
noun
[mass noun]-
the action of improvising: she specializes in improvisation on the piano improvisation is a performer’s greatest creative act
-
[count noun] something that is improvised, in particular a piece of music, drama, etc. created spontaneously or without preparation: free-form jazz improvisations

Derivatives
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Pronunciation: /-ˈzeɪʃ(ə)n(ə)l/
adjective