constellation (n.) Look up constellation at Dictionary.com
early 14c., from Old French constellacion "constellation, conjuncture (of planets)," from Late Latin constellationem (nominative constellatio) "set with stars," from constellatus, from Latin com- "with" (see com-) + past participle of stellare "to shine," from stella "star" (see star). Originally in astrology, of position of planets ("stars") in regard to one another on a given day, usually one's birth day, as a determination of one's character. "I folwed ay myn inclinacioun/By vertu of my constillacioun" (Chaucer, "Wife's Prologue," c.1386). Modern astronomical sense is from 1550s.