While it sounds like a generic reference to all art in contemporary life, the term "Modern art" actually refers to a movement in fine art that began in the 1860s and continued through the early 1970s. What may be confusing is that Modern art isn't actually the most modern art in existence---the term "Contemporary art" actually refers to art that is more recent.
Modern-art paintings were notable for their departure from realistic or literal representation of the real world. Modern-art paintings often tried to capture abstractions such as music, rhythm, thoughts and emotions, or specific qualities of light or form in innovative and experimental ways.
Modern-art paintings may be subdivided into movements all stemming from, and influenced by, the environment of experimentation and the political and cultural attitudes of the times. These movements include Expressionism, Cubism, Dadaism, Fauvism and Surrealism.
Famous painters in the Modern-art movement included Monet, Van Gogh, Picasso, Cezanne, Kandinsky, Pollock and Warhol. This is just a small handful of many famous Modern-art painters.
Modern-art paintings may be representational or nonrepresentational. The common denominator among all movements in Modern art is the presence of an individual theory, belief or convention that spurred their development. For example, the Dada artists embraced the rejection of reason and logic. They applied this credo to their art as well as their political beliefs, writings and everyday lives.
Modern art represented a departure from earlier traditions in art because it redefined the convention of paintings. Previous to Modern art, most paintings were strictly representational (as in the case of portraiture and landscapes) or religious and/or allegorical in nature.