blue

of the color intermediate between green and violet; having a color similar to that of a clear unclouded sky;, Helen Hunt Jackson

October's bright blue weather

used to signify the Union forces in the American Civil War (who wore blue uniforms)

a ragged blue line

blue color or pigment; resembling the color of the clear sky in the daytime

he had eyes of bright blue

blue clothing

she was wearing blue

any organization or party whose uniforms or badges are blue

the Union army was a vast blue