From Brewer:
Pleiades (3 syl.) means the “sailing stars” (Greek, pleo, to sail), because the Greeks considered navigation
safe at the return of the Pleiades, and never attempted it after those stars disappeared.
The PLEIADES were the seven daughters of Atlas and Pleione. They were transformed into stars, one
of which (Merope) is invisible out of shame, because she alone married a human being. Some call the
invisible star “Electra,” and say she hides herself from grief for the destruction of the city and royal race
of Troy.