n.
Function: noun
Date: 13th century
1 : a color whose hue is that of the clear sky or that of the portion of the color spectrum lying between green and violet
2 a : a pigment or dye that colors blue b : BLUING
3 a : blue clothing or cloth b plural : a blue costume or uniform
4 a : a Union soldier in the American Civil War b often capitalized : the Union army
5 a (1) : SKY (2) : the far distance <disappeared into the blue > b : SEA
6 : a blue object
7 : BLUESTOCKING
8 : any of numerous small chiefly blue butterflies (family Lycaenidae)
9 : BLUEFISH
10 : BLUE CHEESE
– out of the blue : without advance notice : UNEXPECTEDLY <the job offer came out of the blue >