What is Dewey's definition of expression?

Drawing from naturalistic roots, Dewey posited that every experience began with what he deemed an “impulsion,” or a need arising from interaction from the environment. Impulsion differed from impulse in that it served as the catalyst for a larger experience, whereas impulse was a single, smaller reaction. According to Dewey, what we think of as artistic expression does not arise through a sudden burst of energy or emotion, but requires extensive observation, reflection, as well as a conjoining of past and present experiences. Dewey viewed expression holistically, valuing the experience of the entire artistic process over its end result, or “expressive object,” although the expressive object served as a platform for encounter between artist and observer. This type of sensory exchange draws heavily from both biological and psychological theories, and functional psychology in particular.
https://digitalcommons.trinity.edu/cgi/viewcontent.cgi?article=1008&context=art_faculty

https://plato.stanford.edu/entries/dewey-aesthetics/