Emily Dickinson Lexicon

PLEI'ADS, n. [ple'yads; L. Pleiades; Gr. πλειαδες, supposed to be formed from πλεω, to sail, as the rising of the seven stars indicated the time of safe navigation.]

In astronomy, a cluster of seven stars in the neck of the constellation Taurus. The Latins called them Vergiliæ, from ver, spring, because of their rising about the vernal equinox. – Encyc. Ainsworth.