Definition:(noun) - Collage derives its name from the French verb coller, to glue. The work of art is made by gluing things to the surface. Collage became an art form during the Synthetic Cubist period of Picasso and Braque. At first, Pablo Picasso glued oil cloth to his surface of Still Life with Chair Caning in May of 1912. He glued a rope around the edge of the oval canvas. Georges Braque then glued imitation wood-grained wallpaper to his Fruit Dish and Glass (September 1912). Braque's work is called papier collé (glued or pasted paper), a specific type of collage.
During the Dada movement, Hannah Höch (German, 1889-1978) glued bits of photographs from magazines and advertising in such works as Cut with a Kitchen Knife, (1919-20). Fellow Dadaist Kurt Schwitters (German, 1887-1948) also glued bits of paper he found in newspapers, advertisements and other discarded matter beginning in 1919. Schwitters called his collages and assemblages Merzbilder, a word derived from the German word "Kommerz" (Commerce, as in banking) which had been on a fragment of an advertisement in his first work, and bilder ("pictures").
The exclusive use of photos in collage is called photomontage.
Collage became the way to integrate "high" and "low" art - work made by the artist's hand and work made by mass-production.