symphonism
noun
sym·pho·nism ˈsim(p)-fə-ˌni-zəm 
1
: musical composition in a symphonic style
especially : musical composition of complexity and seriousness of purpose regarded as appropriate to the symphony
… their suspicion of the abstract symphonic genre was deeply rooted enough to provoke calls for a new kind of proletarian symphonism based on mass song. 
Pauline Fairclough, A Soviet Credo, 2006
Pauline Fairclough, A Soviet Credo, 2006 2
: the writing of symphonies
So Debussy and Satie began to seek a way out of the hulking fortresses of Beethovenian symphonism and Wagnerian opera. Alex Ross, The Rest Is Noise, 2007
Alex Ross, The Rest Is Noise, 2007
Word History
Etymology
symphony + -ism, after Russian simfonizm
Note: The word simfonizm as a musicological term in this sense was introduced by the Russian composer and critic Boris Vladimirovič Asaf'ev (1884-1949; pseudonym, "Igor' Glebov") in an article "Puti v buduščee" ("Paths to the future"), Melos, vypusk 2, St. Petersburg, 1918.
First Known Use
1916, in the meaning defined above