IPA: /nɒnˈθiːətrɪkəl/
KK: /nɑnˈθiːətrɪkəl/
Not related to or characteristic of the theater or dramatic performances.
The film festival included many nontheatrical works that focused on documentary storytelling.
Nontheatrical → It is formed from "non-" (meaning not) and "theatrical" (from Greek "theatron", meaning a place for viewing). The word "nontheatrical" means not related to or characteristic of a theater or theatrical performance.
Think of 'non-' meaning not, and 'theatrical' referring to theater — so nontheatrical describes something that is not related to theater.