kənˈvenchən ə lˌizəm, -chnəˌli- noun
( -s )
1. : observance of or tendency to observe conventions
such social compulsives as fear of ridicule, desire for public esteem, prestige, social habits — all that J. S. Mill included in “the authority of Conventionalism ” — Jerome Frank
2. : a conventional practice, usage, or principle
he thanked his soldiers after a victory, but he did not order Te Deums to be sung for it; and in the absence of these conventionalisms he perhaps showed more real reverence — J.A.Froude
3. : a theory that regards the principles of logic, mathematics, or science as conventions (sense 1e) or as true by convention