Why are the Blues called blues?

Related questions

1. What do you call a songwriter?
2. What made the blues popular?
3. How many bars are in a verse?
4. What is the style of R&B?
5. What exactly is R&B?
6. What is the 12 bar blues structure?
7. What is the difference between R&B and contemporary R&B?
8. Who proclaimed himself the father of the blues?
9. Who is an R&B singer?
10. Who created contemporary R&B?

Tags

1. #agitation
2. #alcohol
3. #great
4. #devils
5. #shortened
6. #severe
7. #originated
8. #american
9. #probably
10. #music
11. #english
12. #hallucinations
13. #expression
14. #depression
15. #century
16. #intense
17. #blues
18. #visual
19. #state
20. #accompany
21. #withdrawal