As in English there can be different words in Spanish for basically the same thing.
We have brown, tan, coffee and if we're talking about hair brinette too.
There is also variation in the words used in different parts of the world too. Spanish is spoken in most of South Ametica, each country has some of its own words.
Much thd same as British English, American English, Australian English etc.
Report, because in general the comment section is not what Duolingo uses to make changes. Duolingo's default is U.S. English, and sometimes (especially with newer lessons/exercises), anything else is not yet in its database of acceptable answers. "Grey" is not the preferred spelling in U.S. English, so it may just have been overlooked.
This color is also called 'maroon', but that is not accepted for an answer. Just coming back to duolingo after a long time with a pretty good level of Spanish but it takes AGES to test through all of it because these things and other minor things aren't considered correct ffs. On the verge of just giving up again. Seems like Duolingo is only useful or usable if you're just starting out with a new language. Not possible to improve an existing language without getting through many painful tests like these where common words aren't considered correct. Especially an issue because I'm learning Spanish, native language is Dutch, and everything goes through English making it subtly more difficult.
Gray or maroon should be correct. Funny enough the last few years I got tons of emails of corrections that are accepted, sometimes YEARS after submitting them. What's up with this? Just fix this system so that Duolingo is also useful for novices, please.