diff --git a/src/schema/objects/entities.yaml b/src/schema/objects/entities.yaml
index 6facc34c0d..bab521a271 100644
--- a/src/schema/objects/entities.yaml
+++ b/src/schema/objects/entities.yaml
@@ -422,3 +422,22 @@ tracksys:
     may be longer and more human readable.
   type: string
   format: label
+stimulus:
+  name: stim
+  display_name: Stimulus
+  description: |
+    The `stim-<label>` entity can be used to distinguish stimulus files stored in the `stimuli/` directory.
+
+    This entity is only applicable to stimulus files.
+  type: string
+  format: label
+annotation:
+  name: annot
+  display_name: Annotation
+  description: |
+    The `annot-<label>` entity can be used to distinguish different annotations
+    of the stimlus data.
+
+    This entity is only applicable to stimulus files.
+  type: string
+  format: label
diff --git a/src/schema/rules/entities.yaml b/src/schema/rules/entities.yaml
index 2194a61a92..8d86c87d9e 100644
--- a/src/schema/rules/entities.yaml
+++ b/src/schema/rules/entities.yaml
@@ -30,3 +30,5 @@
 - density
 - label
 - description
+- stimulus
+- annotation