Indigo
noun
The kanji and the word are exactly the same. That means they share meanings as well.
Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You learned this reading already, so you should know this too!
藍染の藍は天然ですが、ジーンズに使われる合成インディゴは人工的なものです。
Indigo plant dye is natural, but the synthetic dye used for jeans is artificial.