diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
index adc4eaeb0..a244205d2 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/BaseWorkerContext.java
@@ -415,18 +415,18 @@ public abstract class BaseWorkerContext implements IWorkerContext {
   }
   
   @Override
-  public ValueSetExpansionOutcome expandVS(ConceptSetComponent inc, boolean heirachical) throws TerminologyServiceException {
+  public ValueSetExpansionOutcome expandVS(ConceptSetComponent inc, boolean hierarchical) throws TerminologyServiceException {
     ValueSet vs = new ValueSet();
     vs.setCompose(new ValueSetComposeComponent());
     vs.getCompose().getInclude().add(inc);
-    CacheToken cacheToken = txCache.generateExpandToken(vs, heirachical);
+    CacheToken cacheToken = txCache.generateExpandToken(vs, hierarchical);
     ValueSetExpansionOutcome res;
     res = txCache.getExpansion(cacheToken);
     if (res != null)
       return res;
     Parameters p = expParameters.copy(); 
     p.setParameter("includeDefinition", false);
-    p.setParameter("excludeNested", !heirachical);
+    p.setParameter("excludeNested", !hierarchical);
     
     if (noTerminologyServer)
       return new ValueSetExpansionOutcome("Error expanding ValueSet: running without terminology services", TerminologyServiceErrorClass.NOSERVICE);
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/IWorkerContext.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/IWorkerContext.java
index 6d04f3731..cff885a58 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/IWorkerContext.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/IWorkerContext.java
@@ -281,7 +281,7 @@ public interface IWorkerContext {
    * @return
    * @throws FHIRException 
    */
-  public ValueSetExpansionOutcome expandVS(ConceptSetComponent inc, boolean heirarchical) throws TerminologyServiceException;
+  public ValueSetExpansionOutcome expandVS(ConceptSetComponent inc, boolean hierarchical) throws TerminologyServiceException;
   
   public class ValidationResult {
     private ConceptDefinitionComponent definition;