I was wondering how you would categorize certain forms of music, and was hoping that somebody could help me out.

I know that sectional forms are the binary ternary etc, developmental forms are forms such as sonata form, cyclical form entails concertos and symphonies to name a few... but what type of musical form are pieces such as: preludes, ├ętudes, bagatelles, motets, chansons and so on. Are they simply genres? I wouldn't call a prelude a genre of music, so how else could you categorize these types of music?