> Hundreds of years ago, the Japanese language included words for only four basic colors: black, white, red, and blue. If you wanted to describe something green, you’d use the word for blue—“ao”—and that system worked well enough until roughly the end of the first millennium, when the word “midori” (originally meaning “sprout”) began showing up in writing to describe what we know as green.

There's something going on here that the article doesn't explain.

The new word is written 緑, which is also [the Japanese simplified spelling of] the Chinese word that means green in specific. But the Chinese word has always referred to a color, and it's never meant "sprout" -- the shuowen jiezi, written 800 years before the period the article indicates, defines it "帛靑黃色也"!

So by the time this word is being written down, there is no sense of the concept "sprout" at all.

The article seems to present this as a case of conceptual innovation internal to Japanese, which would have been much cooler than the apparent reality of the Japanese starting to use an already well-established concept more often.

Now I want to know why, if midori originally meant "sprout", it does not seem to have the spelling 芽 ("sprout" - 萌芽也) as a possibility...?