Impressionism in music straddles the border between style and period because of its placement between the Romantic period and the 20th Century. It began many of the experiments in new ways of writing music that 20th Century music is known for, such as using exotic and synthetic (made-up) scales and new ways of constructing and combining chords.
The term ‘impressionism’ originally came from a movement in the visual arts in which artist like Monet, Renoir, and Degas depicted their subject matter without sharp contours or minute detail, giving an overall impression of the scene, it’s mood, and atmosphere, rather than an accurate depiction. In music the term was somewhat misplaced since impressionist music far from lacks detail but there are certain parallels between impressionist painting and impressionist music, such as an emphasis on mood, atmosphere, and colour.
What is remarkable about impressionism in music is that we acknowledge it largely because of just two French composers, Claude Debussy and Maurice Ravel – though Debussy himself didn’t much like the term ‘impressionism’, and both Debussy’s and Ravel’s music differ from one another in many ways.