Art Nouveau was an art style that surged to popularity in Europe and the US during the late 19th and early 20th centuries. Its forms and figures could be described as natural, organic, or flowing. Its general style was a very different from the bold, geometrical shapes of its successor, the Art Deco style.

Marcel Duchamp was a member of the global Dada movement, a school of artists from Zurich, Paris, Cologne, Berlin, and New York between 1916 and 1925. Kahlo, Ernst, and Miró were all members of the Surrealist movement, which occurred during the same era and employed a mixture of psychoanalysis, mysticism, and symbolism to reveal unconscious thoughts.

Silkscreen printing is an old form of printing, but received a boost in the mid-twentieth century when advances in more quickly placing ink onto a canvas became possible. The artist who most enthusiastically adopted the method was Andy Warhol. Silkscreen printing allowed Warhol to quickly copy multiple images in different, usually bright, colors on one canvas. This very effect is captured by the dozens of images of Marilyn Monroe that Warhol printed in his Marilyn Diptych of 1962.

Ansel Adams is well known for two related things: his sweeping black and white photographs of the American West and his many books and classes teaching photography. Most significant in relation to the latter is his development of the "Zone System." The Zone System set down specific parameters to achieve the optimal light, focus, and composition in the development of the film.

Abstraction is a style of art that reduces shapes and appearances to basic yet recognizable forms. For example, a stick figure is an abstraction of a human being. The form of the human figure is greatly reduced to its most basic components, but it still recognizable. Generally you can think of it as the opposite of naturalism, a style that seeks to reproduce the forms of things as they appear in nature.

Cubism is typically involves an abstract representation of a subject into various geometric shapes, each from a different perspective.

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"Provenance" is exclusive to art, whereas "ancestry" applies to people and "record" is less specific; provenance is essential to prove the legitimacy and authenticity of both modern and older paintings. (This question is not limited to the scope of twentieth and twenty-first century art, but has arguably become more important in this period.)

Roy Lichtenstein became famous in the 1960s through a series of large canvasses that were directly copied from comic books. Using comic book images as inspiration, Lichtenstein also applied a technique known as Ben-Day Dots, the stenciling of small dots that colored comic books in the era. Lichtenstein would continue to use the technique in his later career, when he was no longer directly adapting images from comic books.

Drip painting is most closely associated with the twentieth-century American painter Jackson Pollock, whose signature works involved Pollock splattering, splashing, and slowly dripping paint directly onto canvasses that were laid on the ground. The technique was used almost contemporaneously by the artist Janet Sobel, and has been consistently used by a small cadre of artists from the 1950s to the present.

Grant Wood lived almost his entire life in the state of Iowa, teaching at schools and supporting organizations in the state. His painting reflected this attachment to his native region, and were articulated by Wood, along with Thomas Hart Benton, into an artistic style known as "regionalism." Wood's most famous work "American Gothic," featuring a farming couple in an honest, empathetic, yet slightly off perspective, is emblematic of the style.