Few put it better than Tolstoy (from "What is Art?"):
"Art is a human activity, consisting in this, that one man consciously, by means of certain external signs, hands on to others feelings he has lived through, and that other people are infected by these feelings, and also experience them.
Art is not, as the metaphysicians say, the manifestation of some mysterious Idea of beauty, or God; it is not, as the æsthetical physiologists say, a game in which man lets off his excess of stored-up energy; it is not the expression of man’s emotions by external signs; it is not the production of pleasing objects; and, above all, it is not pleasure; but it is a means of union among men, joining them together in the same feelings, and indispensable for the life and progress towards well-being of individuals and of humanity.
As, thanks to man’s capacity to express thoughts by words, every man may know all that has been done for him in the realms of thought by all humanity before his day, and can, in the present, thanks to this capacity to understand the thoughts of others, become a sharer in their activity, and can himself hand on to his contemporaries and descendants the thoughts he has assimilated from others, as well as those which have arisen within himself; so, thanks to man’s capacity to be infected with the feelings of others by means of art, all that is being lived through by his contemporaries is accessible to him, as well as the feelings experienced by men thousands of years ago, and he has also the possibility of transmitting his own feelings to others."
Full text: https://www.gutenberg.org/files/64908/64908-h/64908-h.htm