Senior Concept Artist at @SES_dev, working on @Astroneergame | Prev: Valve, Runic Games, Riot Games, Toys for Bob, Microsoft, NASA 
|http://artstation.com/ness
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Not sure what your fields are, but I'm speaking as a video game concept artist where there is a clear delineation. For example, at Riot Games there are separate roles for splash artists (illustrators) and concept artists (designers)--
--I'm not saying there can't be overlap, but they serve different purposes in the game industry, and people confuse them all the time. Quick and dirty explanation over here:https://twitter.com/____ness/status/1001703786073731072 …
I see what you mean! I'm pretty green, but involved in the theoretics of illustration - which obviously is a discipline that straddles art and design, and branches out past game design. Perhaps it would be better for our lexicon to have more definitive summaries of roles? ...
as a lot of designers would classify themselves as illustrators too. Illustration is an incredibly large spectrum that can, and if someone's work that involves a heavy amount of mathematics/architecture can also fall under that branch!
x a bajillion
Clarification via context: ‘I’m a decent concept artist but a dogshit illustrator’
I read your explanation first 
I think because the subject was just about 'creatives' that your initial tweet was too, but I don't know the correct terminology for the game industry, I'm more animation/book illustrations, so fair does if that's what you were referring to 
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.
if Illustration isn't concept art and vice versa, those who dabble in both and storyboarding, character design etc might feel like they can no longer just call themselves 'illustrators' simply because a piece is not finished 