fundamentalism

Etymology

fundamental + -ism. Started being used in the 1910s by American Christians.

noun

1. (religion) The tendency to reduce a religion to its most fundamental tenets, based on strict interpretation of core texts.
2. (by extension) A rigid conformity to any set of basic tenets.
   Recent books by philosopher Roger Scruton (1999, 2000) and music educator Robert Walker (2007) may be interpreted as a last desperate gasp of this form of musical fundamentalism or neoconservativism—the kind that tells the masses what is "good for them" on the grounds that they lack adequate bases for judgments on their own […] 2009, Thomas A. Regelski, J. Terry Gates, Music Education for Changing Times: Guiding Visions for Practice
3. (finance) The belief that fundamental financial quantities are the best predictor of the price of a financial instrument.