It was first used in the early 20th century to describe a new art technique where various materials like paper, fabric, and other objects were glued onto a surface to create a piece of art.
The term was likely coined by French artists, as the movement was popularized in France, particularly by Cubist artists like Georges Braque and Pablo Picasso.
So, the essence of the word "collage" reflects the act of sticking things together using glue.