Conventional is an adjective for things that are normal, ordinary, and following the accepted way. Ho-hum.
This word describes what is typical and ordinary and that which follows accepted standards of behavior or taste. This is a word that's current definition is still very similar to its Latin root, conventionalis, which is "pertaining to an agreement." One way this word is used is with respect to conventional weapons, as in those "not using, making, or involving nuclear weapons or energy; nonnuclear."