blue-black has definitions from the field of color
1
[ adjective ] black with a tinge of blue and no hint of brown

Used in print

(S. J. Perelman, The Rising Gorge. New York:...)

She was a living doll and no mistake - the blue-black bang , the wide cheekbones , olive flushed , that betrayed the Cherokee strain in her Midwestern lineage , and the mouth whose only fault , in the novelist 's carping phrase , was that the lower lip was a_trifle too voluptuous .

Related terms

achromatic

2
[ adjective ] (color) having a color similar to that of a clear unclouded sky

Examples

"October's bright blue weather"- Helen Hunt Jackson "a blue flame" "blue haze of tobacco smoke"

Related terms

chromatic

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