English Reference

Word

indigo

Phoneticsin·di·go

US/ˈɪndəˌɡoʊ/

UK/ˈɪndɪɡˌəʊ/

Definitions

01color

B2

adj. having a dark, purplish-blue color.

adj. possessing a deep, dark blue or violet-blue hue, typically associated with the spectrum between blue and violet.

“The sky turned a deep indigo just before the stars appeared.”

“The artist used indigo pigments to capture the moody, atmospheric quality of the ocean at twilight.”

Synonyms

deep blueviolet-blue

02the color or dye

B2

n. a dark blue color or the substance used to dye clothes this color.

n. a deep blue dye traditionally extracted from plants of the genus Indigofera, or the specific color produced by such a dye.

“Indigo was once a very expensive dye used for royal clothing.”

“Synthetic indigo revolutionized the textile industry, making the deep blue color of denim jeans affordable for mass production.”

Synonyms

03the plant

C1 · Science

n. a type of plant that people use to make blue dye.

n. any of various plants, especially those in the genus Indigofera, from which the blue dye is obtained.

“Farmers in the region used to grow indigo as their main crop.”

“The cultivation of indigo required specific soil conditions and intensive labor to process the leaves into usable pigment blocks.”

Technical

Synonyms

Indigofera

Real-World Examples

“Melo explains that there's indigo, which is blue, "brominated" indigo, which is purple, and indirubin, which is red.”
BBC Future · 24 Nov 2023
“The other face of the double-sided medal features a gold and indigo pattern designed by First Nations artist Ambrose Killian.”
BBC News · 22 Aug 2026

Etymology

16th century (as indico, modern spelling from the 17th century), Spanish índigo, Portuguese endego (modern índigo), or Dutch (via Portuguese) indigo, all from Latin indicum (“indigo”), from Ancient Greek ἰνδικόν (indikón, “Indian dye”), from Ἰνδία (Indía). Doublet of Indic.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Idioms

green indigo — Synonym of lokao.

This entry

Level
B2 · Upper Intermediate
Frequency
Frequent
Updated

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English Reference