exposition

noun

1.
a systematic interpretation or explanation (usually written) of a specific topic
Derived from:
exposit
2.
a collection of things (goods or works of art etc.) for public display
3.
an account that sets forth the meaning or intent of a writing or discourse
Derived from:
exposit
4.
(music) the section of a movement (especially in sonata form) where the major musical themes first occur