Update docs/terminology.md

Co-authored-by: John Gerrard Holland <[email protected]>

docs/terminology.md

@@ -5,7 +5,7 @@ The following table includes naming conventions used throughout AutoRA.
 | Term               | Description                                                                                                                                 | Relevant Modules                                |
 |--------------------|---------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------|
 | State              | Base object that has all relevant fields and which uses the Delta mechanism to modify those fields.                                         | Core                                            |
-| Delta              | An object that determines the extension behavior of State objects.                                                                          | Core                                            |
+| Delta              | An object with new data that can be added to a State, returning a new State which includes the new data.                                                                          | Core                                            |
 | StandardState      | An optional default State that has the following fields: variables, conditions, experiment_data, models.                                    | Core                                            |
 | Variables          | A State field that holds experimental variables, which are defined according to name, type, units, allowed values, and range.               | Experimentalists, Experiment Runners, Theorists |
 | VariableCollection | Immutable metadata about dependent variables, independent variables, and covariates.                                                        | Experimentalists, Experiment Runners, Theorists |