Abstract expressionism
This art style was prominent for about one generation. With its roots in New York, it started in World War II times and ended in the Korean War times. You may have heard of surrealism? The leaders of that movement lived in the U.S. (in exile) during World War II. AE was a mix of surrealism and some other concepts--notably expressionism. The influence of American culture is heavy in this form of art. The two main categories of AE are iconic and calligraphic. 
A term originally used to describe Wassily Kandinsky's abstract paintings of the 1920's, but really first used in the modern sense in 1946 to describe contemporary painting. It was popular from that time until the end of the 1950's. Many painters are still painting in this style. It is the first art movement to have both a European and American background. It was influenced by the artists fleeing Hitler, such as Max Ernst, Fernand Leger, and Piet Mondrian. The term is just what it implies. The paintings are abstractions or no noticeable relation to anything in nature at all. The object is to express the inner feelings of the artist toward the subject or the surface that the painting is on. It is as much an emotional release for the artist as it is anything else. Look at works by Robert Motherwell, Willem De Kooning, Mark Rothko, and Jackson Pollock.
