Ad Libitum

Ad Libitum (in Ital., a piacere, or a piacimento) is a musical term which implies that the part so marked may be performed according to the taste of the performer, and not necessarily in strict time. When there is an accompaniment to the music thus marked, it must strictly follow the ad libitum time of the principal performer. Ad Libitum also frequently means, that a part for a particular instrument or instruments, in instrumental scores or pianoforte arrangements, may either be played or entirely left out.