exposition

definition: (music) the section of a movement (especially in sonata form) where the major musical themes first occur
example:
speech part: noun
synonyms:
definition: an account that sets forth the meaning or intent of a writing or discourse
example: we would have understood the play better if there had been some initial exposition of the background
speech part: noun
synonyms:
definition: a systematic interpretation or explanation (usually written) of a specific topic
example:
speech part: noun
synonyms: expounding
definition: a collection of things (goods or works of art etc.) for public display
example:
speech part: noun
synonyms: exhibition

How exposition is being used?