I was just remembering there was this infographic that made the point she's not cyan, but I don't remember what the correct color was supposed to be.

Rainbow.
In a flashback rainbow Dash's father has a rainbow mane, Her mane and tail are rainbow.
Her coat is Cyan.

Turquoise is the shade of blue her coat is if you want to be specific

sky blue, it's simply its just not one word, but does every colour have to be one word?

You could call it "cyan," "light blue," "sky blue," "aquamarine" or "cerulean." Really, it makes no difference what you call it—those colors are only a shade or two apart.

727206
Uh... turquoise is blue and green mixed together, buddy...

As far as I can tell, the only shade of green in her entire body is in her mane...

727276 Turquoise is Rainbow Dash's color, You could also use Aqua, Electric Cyan or Blue-Green.
Cyan is unspecific, Everyone simply jumps to the conclusion that Cyan is Aqua, Blue-Green, Electric Cyan or Turquoise. This is a very common mistake.

Turquoise however is a specific color, Cyan is unspecific, If you want CYAN like everyone thinks its called Electric Cyan.

A very common mistake.
Never jump to the conclusion that Cyan is a full color cause it isn't really, its a color category.
Don't believe me? Here you go.

http://en.wikipedia.org/wiki/Cyan

Electric Cyan is to bright in my opinion to be Rainbow Dash.
Turquoise is the true color in my opinion of Rainbow Dash if I were to describe her.
Why? Its not so blindingly bright blue, Its perfect and it is the color they most likely used to color her on the show.

Turquoise is in Cyan's color category.

-Rezz

Dash is based off of a pink pony named firefly if that's what you mean. Otherwise, she's sky blue, because that's what her color's based off of. I also like "cerulean" or "azure".

I believe the tech term for it's "columbia blue."

post above is true

727675
Exactly what I was looking for. Thank you.

Rainbow dash is colombian blue i think

She is true blue, and that is all that is necessary.

727675
You have the link for that, I'd like to read it in depth

Cyan is not a color. :V