Emily Dickinson Lexicon

MYR'I-AD, n. [Gr. μυριας, from μυριος, extreme, innumerable; W. myr, that is, infinite, fluctuating, ants, emmets; myrz, infinity; a myriad, ten thousand. Here we see the origin of the Gr. μυρμος, μυρμηξ, an ant, so named from numbers or motion. See Fervent.]

1. The number of ten thousand.
2. An immense number, indefinitely. Milton.