Synonyms:
* Edge: This is a general synonym that refers to the outer boundary of something.
* Border: Similar to "edge," but often implies a line or separation.
* Margin: This refers to the outer or less important part of something.
* Perimeter: This refers to the outer boundary of a two-dimensional shape.
* Rim: This specifically refers to the outer edge of a circular object.
* Outskirts: This refers to the outer areas of a town or city.
Antonyms:
* Center: This refers to the middle or most important part of something.
* Core: This refers to the essential part of something.
* Mainstream: This refers to the prevailing or most common trends or ideas.
* Heart: This refers to the central or most important part of something.
* Interior: This refers to the inside of something.
The best synonym or antonym will depend on the specific context in which you are using the word "fringe."