Improve description of fragment

Co-authored-by: Maria Elisabeth Schreiber <maria.schreiber@apollographql.com>

docs/source/data/fragments.mdx

@@ -3,7 +3,7 @@ title: Fragments
 description: Share fields between operations
 ---
 
-A [GraphQL fragment](http://graphql.org/learn/queries/#fragments) is a piece of logic that can be shared between multiple queries and mutations. Fragments are especially useful when [colocated with components](#colocating-fragments) to define the component's data requirements.
+A [GraphQL fragment](http://graphql.org/learn/queries/#fragments) is a set of fields you can reuse across multiple queries and mutations. Fragments are especially useful when [colocated with components](#colocating-fragments) to define the component's data requirements.
 
 Here's the declaration of a `NameParts` fragment that can be used with any `Person` object: