preview

The definition of a preview is a show of something before it is finally released.

(noun)

An example of a preview is a sneak peek at a film that is coming soon to theaters.

To preview is to see or hear something before it is finalized.

(verb)

An example of preview is to look at an art exhibit before the exhibit is open to the public.
An example of preview is to hear parts of a speech before it is given at a meeting.

See preview in Webster's New World College Dictionary

transitive verb

to view or show beforehand; receive or give a preview of

noun

☆ a previous or preliminary view or survey
☆
1. a restricted showing, as of a film, before exhibition to the public generally
2. a showing of scenes from a film, TV show, etc. in advertising its coming appearance

See preview in American Heritage Dictionary 4

also pre·vue

noun

An advance showing, as of a movie or art exhibition, to which a selected audience is invited before public presentation begins.
An advance viewing or exhibition, especially the presentation of several scenes advertising a forthcoming movie; a trailer.
An introductory or preliminary message, sample, or overview; a foretaste.

transitive verb pre·viewed also pre·vued, pre·view·ing also pre·vu·ing, pre·views also pre·vues