Entry 1 sense Webster, 1913 Pianissimo · Pi·a·nis·si·mo · IPA /ˌpi.əˈnɪsɪmoʊ/ 01 a. Very soft; -- a direction to execute a passage as softly as possible. (Abbrev. pp.) 1. Very soft; -- a direction to execute a passage as softly as possible. (Abbrev. pp.)(Mus.)