What is the meaning of blues?

noun

• Blue color or pigment; resembling the color of the clear sky in the daytime.
  • usage: "he had eyes of bright blue"
  • synonyms: blue, blueness
• Blue clothing.
  • usage: "she was wearing blue"
  • synonyms: blue
• Any organization or party whose uniforms or badges are blue.
  • usage: "the Union army was a vast blue"
  • synonyms: blue
• The sky as viewed during daylight.
  • usage: "he shot an arrow into the blue"
  • synonyms: blue sky, blue, blue air, wild blue yonder
• Used to whiten laundry or hair or give it a bluish tinge.
  • synonyms: bluing, blueing, blue
• The sodium salt of amobarbital that is used as a barbiturate; used as a sedative and a hypnotic.
  • synonyms: amobarbital sodium, blue, blue angel, blue devil, Amytal
• Any of numerous small butterflies of the family Lycaenidae.
  • synonyms: blue
• A type of folksong that originated among Black Americans at the beginning of the 20th century; has a melancholy sound from repeated use of blue notes.
• A state of depression.
  • usage: "he had a bad case of the blues"
  • synonyms: blue devils, megrims, vapors, vapours

verb

• Turn blue.
  • synonyms: blue