Wikipedia defines concept art as “a form of illustration where the main goal is to convey a visual representation of a design, idea, and/or mood for use in films, video games, animation, or comic books before it is put into the final product. Concept art is also referred to as visual development and/or concept design. This term can also be applied to retail design, set design, fashion design and architectural design.”
Therefore, concept artists are a sub-branch of illustrators. They work with the Art Director and/or Production designer of a film, game, animation, etc. to create visual representations of an abstract vision. They create new worlds, generate new characters, and bring sci-fi dreams to life. The word on the street is that the field of concept art is very competitive and difficult to break into.
I have posted some works by various concept artists below. What do you think?