plural indigos or indigoes
Definition of indigo
1
: a deep reddish blue
2
: indigo plant
3a
: a blue vat dye obtained from plants (such as indigo plants)
b
: the principal coloring matter C16H10N2O2 of natural indigo usually synthesized as a blue powder with a coppery luster
Test Your Vocabulary
Name That Color
-
- Name that color:

Test your knowledge - and maybe learn something along the way.
TAKE THE QUIZ
A daily challenge for crossword fanatics.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridged
Share indigo
Time Traveler for indigo
The first known use of indigo was in 1555
See more words from the same year