1 [uncountable and countable]CC
the colour of the sky or the sea on a fine day:
She nearly always dresses in blue.
the rich greens and blues of the tapestry
2 [uncountable] also the bluesAPM
a slow sad style of music that came from the southern US: ➔ rhythm and blues
a blues singer
3 [plural] informal
feelings of sadness:
A lot of women get the blues after the baby is born.
if something happens out of the blue, it is very unexpected
➔ a bolt from/out of the blueat bolt1 (3)
5 [countable] British EnglishSEC
someone who has represented Oxford or Cambridge University at a sport, or the title given to such a person