manynessrare.|ˈmɛnɪnɪs| [f. many + -ness.] Plurality, numerosity. 1609Skene Reg. Maj. 115 Be multiplication, or manynes of Hynes.1886Hall & Jastrow in Mind Jan. 60 The sense of manyness..acts as a stimulus to us to bend all available energy to tally as fast as possible.