Answer:

indigo

AnswerCrossword Clue
INDIGOEllington's "Mood .."
INDIGOThe I of ROY G. BIV
INDIGOSpectrum component
INDIGOPrism bar?
INDIGOEllington's "Mood ..."
INDIGOPart of Roy G Biv
INDIGORainbow color
INDIGOPart of Roy G. Biv
INDIGOSpectrum color
INDIGOSpectrum color between blue and violet
INDIGO"Mood ..." (Sinatra song)
INDIGOBlue shade
INDIGO"Mood ..." (Ellington song)
INDIGO... Girls ("Closer to Fine" singers)
INDIGOMusical mood?
INDIGOColor of the rainbow
INDIGO... Girls (singers featured in "Wordplay")
INDIGO... Girls (crossword-loving folk-rock duo)
INDIGO"Mood ...": Ellington
INDIGOBlue dye
INDIGOPart of ROY G. BIV
INDIGOEl Salvador export
INDIGODye source
INDIGOPlum relative
INDIGOPurple shade
INDIGORainbow hue
INDIGOShade of purple
INDIGOCyan + magenta
INDIGOSapphire relative
INDIGOShade of blue
INDIGOSpectrum division
INDIGODuke Ellington's "Mood ..."
INDIGO... Girls ("Closer to Fine" duo)
INDIGOSource of blue.
INDIGOReddish-blue.
INDIGOA color of the rainbow.
INDIGOBluest of blue.
INDIGODark grayish blue.
INDIGOBlue dye.
INDIGO"Mood" of an Ellington piece.