Definition of numerosity in US English:

numerosity

noun

  • Numerousness.

Origin

Late 16th century (in an earlier sense). From post-classical Latin numerositat-, numerositas large number, multitude (early 3rd cent. in Tertullian), rhythmic order from classical Latin numerōsus + -tās.

Pronunciation

numerosity

/ˌnjuːməˈrɒsɪti/