diff --git a/include/tvm/relay/module.h b/include/tvm/relay/module.h
index 262c82df5c5d..7895f32d7e21 100644
--- a/include/tvm/relay/module.h
+++ b/include/tvm/relay/module.h
@@ -104,18 +104,20 @@ class ModuleNode : public RelayNode {
    * \param update Controls whether you can replace a definition in the
    * environment.
    */
-  TVM_DLL void AddDef(const GlobalTypeVar& var, const TypeData& type, bool update = false);
+  TVM_DLL void AddTypeDef(const GlobalTypeVar& var, const TypeData& type, bool update = false);
 
   /*!
-   * \brief Add a type definition to the global environment.
-   * \param var The name of the global function.
+   * \brief Add a type-level definition to the global environment.
+   * \param var The var of the global type definition.
    * \param type The ADT.
    * \param update Controls whether you can replace a definition in the
    * environment.
    *
-   * It does not do type inference as AddDef does.
+   * It does not do kind checking as AddTypeDef does.
    */
-  TVM_DLL void AddDefUnchecked(const GlobalTypeVar& var, const TypeData& type, bool update = false);
+  TVM_DLL void AddTypeDefUnchecked(const GlobalTypeVar& var,
+                                   const TypeData& type,
+                                   bool update = false);
 
   /*!
    * \brief Update a function in the global environment.
@@ -129,7 +131,7 @@ class ModuleNode : public RelayNode {
    * \param var The name of the global type definition to update.
    * \param type The new ADT.
    */
-  TVM_DLL void UpdateDef(const GlobalTypeVar& var, const TypeData& type);
+  TVM_DLL void UpdateTypeDef(const GlobalTypeVar& var, const TypeData& type);
 
   /*!
    * \brief Remove a function from the global environment.
@@ -162,7 +164,7 @@ class ModuleNode : public RelayNode {
    * \brief Collect all global vars defined in this module.
    * \returns An array of global vars
    */
-  tvm::Array<GlobalVar> GetGlobalVars() const;
+  TVM_DLL tvm::Array<GlobalVar> GetGlobalVars() const;
 
   /*!
    * \brief Look up a global function by its name.
@@ -175,7 +177,7 @@ class ModuleNode : public RelayNode {
    * \brief Collect all global type vars defined in this module.
    * \returns An array of global type vars
    */
-  tvm::Array<GlobalTypeVar> GetGlobalTypeVars() const;
+  TVM_DLL tvm::Array<GlobalTypeVar> GetGlobalTypeVars() const;
 
   /*!
    * \brief Look up a global function by its variable.
@@ -196,14 +198,14 @@ class ModuleNode : public RelayNode {
    * \param var The var of the global type definition.
    * \return The type definition.
    */
-  TVM_DLL TypeData LookupDef(const GlobalTypeVar& var) const;
+  TVM_DLL TypeData LookupTypeDef(const GlobalTypeVar& var) const;
 
   /*!
    * \brief Look up a global type definition by its name.
    * \param var The name of the global type definition.
    * \return The type definition.
    */
-  TVM_DLL TypeData LookupDef(const std::string& var) const;
+  TVM_DLL TypeData LookupTypeDef(const std::string& var) const;
 
   /*!
    * \brief Look up a constructor by its tag.
diff --git a/src/relay/ir/alpha_equal.cc b/src/relay/ir/alpha_equal.cc
index b41d381dd827..bef0454432f2 100644
--- a/src/relay/ir/alpha_equal.cc
+++ b/src/relay/ir/alpha_equal.cc
@@ -70,7 +70,7 @@ class AlphaEqualHandler:
       if (lhsm->type_definitions.size() != rhsm->type_definitions.size()) return false;
       for (const auto& p : lhsm->type_definitions) {
         if (!rhsm->ContainGlobalTypeVar(p.first->name_hint) ||
-            !Equal(p.second, rhsm->LookupDef(p.first->name_hint))) {
+            !Equal(p.second, rhsm->LookupTypeDef(p.first->name_hint))) {
           return false;
         }
       }
diff --git a/src/relay/ir/module.cc b/src/relay/ir/module.cc
index 81dae73b6642..fdaa607e380f 100644
--- a/src/relay/ir/module.cc
+++ b/src/relay/ir/module.cc
@@ -185,15 +185,15 @@ void ModuleNode::RegisterConstructors(const GlobalTypeVar& var, const TypeData&
   }
 }
 
-void ModuleNode::AddDef(const GlobalTypeVar& var, const TypeData& type, bool update) {
-  AddDefUnchecked(var, type, update);
+void ModuleNode::AddTypeDef(const GlobalTypeVar& var, const TypeData& type, bool update) {
+  AddTypeDefUnchecked(var, type, update);
   // need to kind check at the end because the check can look up
   // a definition potentially
   CHECK(KindCheck(type, GetRef<Module>(this)) == Kind::kTypeData)
     << "Invalid or malformed typedata given to module: " << type;
 }
 
-void ModuleNode::AddDefUnchecked(const GlobalTypeVar& var, const TypeData& type, bool update) {
+void ModuleNode::AddTypeDefUnchecked(const GlobalTypeVar& var, const TypeData& type, bool update) {
   this->type_definitions.Set(var, type);
   if (!update) {
     // set global type var map
@@ -208,8 +208,8 @@ void ModuleNode::Update(const GlobalVar& var, const Function& func) {
   this->Add(var, func, true);
 }
 
-void ModuleNode::UpdateDef(const GlobalTypeVar& var, const TypeData& type) {
-  this->AddDef(var, type, true);
+void ModuleNode::UpdateTypeDef(const GlobalTypeVar& var, const TypeData& type) {
+  this->AddTypeDef(var, type, true);
 }
 
 void ModuleNode::Remove(const GlobalVar& var) {
@@ -231,16 +231,16 @@ Function ModuleNode::Lookup(const std::string& name) const {
   return this->Lookup(id);
 }
 
-TypeData ModuleNode::LookupDef(const GlobalTypeVar& var) const {
+TypeData ModuleNode::LookupTypeDef(const GlobalTypeVar& var) const {
   auto it = type_definitions.find(var);
   CHECK(it != type_definitions.end())
     << "There is no definition of " << var->name_hint;
   return (*it).second;
 }
 
-TypeData ModuleNode::LookupDef(const std::string& name) const {
+TypeData ModuleNode::LookupTypeDef(const std::string& name) const {
   GlobalTypeVar id = this->GetGlobalTypeVar(name);
-  return this->LookupDef(id);
+  return this->LookupTypeDef(id);
 }
 
 Constructor ModuleNode::LookupTag(const int32_t tag) {
@@ -257,13 +257,13 @@ void ModuleNode::Update(const Module& mod) {
     this->AddUnchecked(pair.first, pair.second);
   }
   for (auto pair : mod->type_definitions) {
-    this->AddDefUnchecked(pair.first, pair.second);
+    this->AddTypeDefUnchecked(pair.first, pair.second);
   }
   for (auto pair : mod->functions) {
     this->Update(pair.first, pair.second);
   }
   for (auto pair : mod->type_definitions) {
-    this->UpdateDef(pair.first, pair.second);
+    this->UpdateTypeDef(pair.first, pair.second);
   }
 }
 
@@ -347,7 +347,7 @@ TVM_REGISTER_GLOBAL("relay._module.Module_Add")
 });
 
 TVM_REGISTER_GLOBAL("relay._module.Module_AddDef")
-.set_body_method<Module>(&ModuleNode::AddDef);
+.set_body_method<Module>(&ModuleNode::AddTypeDef);
 
 TVM_REGISTER_GLOBAL("relay._module.Module_GetGlobalVar")
 .set_body_method<Module>(&ModuleNode::GetGlobalVar);
@@ -376,12 +376,12 @@ TVM_REGISTER_GLOBAL("relay._module.Module_Lookup_str")
 
 TVM_REGISTER_GLOBAL("relay._module.Module_LookupDef")
 .set_body_typed([](Module mod, GlobalTypeVar var) {
-  return mod->LookupDef(var);
+  return mod->LookupTypeDef(var);
 });
 
 TVM_REGISTER_GLOBAL("relay._module.Module_LookupDef_str")
 .set_body_typed([](Module mod, std::string var) {
-  return mod->LookupDef(var);
+  return mod->LookupTypeDef(var);
 });
 
 TVM_REGISTER_GLOBAL("relay._module.Module_LookupTag")
diff --git a/src/relay/pass/eta_expand.cc b/src/relay/pass/eta_expand.cc
index 672d551113ee..b9973f3da1f3 100644
--- a/src/relay/pass/eta_expand.cc
+++ b/src/relay/pass/eta_expand.cc
@@ -101,7 +101,7 @@ class EtaExpander : public ExprMutator {
       params.push_back(VarNode::make("eta_expand_param", param_type));
     }
     tvm::Array<Type> type_params;
-    TypeData adt_def = mod_->LookupDef(cons->belong_to);
+    TypeData adt_def = mod_->LookupTypeDef(cons->belong_to);
     for (const auto& type_var : adt_def->type_vars) {
       type_params.push_back(type_var_replacer_.VisitType(type_var));
     }
diff --git a/src/relay/pass/kind_check.cc b/src/relay/pass/kind_check.cc
index 5b7e1c004735..081f132d0612 100644
--- a/src/relay/pass/kind_check.cc
+++ b/src/relay/pass/kind_check.cc
@@ -139,7 +139,7 @@ struct KindChecker : TypeFunctor<Kind(const Type&)> {
 
     // finally we need to check the module to check the number of type params
     auto var = GetRef<GlobalTypeVar>(gtv);
-    auto data = mod->LookupDef(var);
+    auto data = mod->LookupTypeDef(var);
     if (data->type_vars.size() != op->args.size()) {
       ReportFatalError(RELAY_ERROR("Expected " << data->type_vars.size() << "arguments for " << tc
                                    << "; got " << op->args.size()));
diff --git a/src/relay/pass/match_exhaustion.cc b/src/relay/pass/match_exhaustion.cc
index 2392b18e768f..6e18c630d2a7 100644
--- a/src/relay/pass/match_exhaustion.cc
+++ b/src/relay/pass/match_exhaustion.cc
@@ -183,7 +183,7 @@ Array<Pattern> ExpandWildcardsConstructor(const PatternConstructor& clause_ctor,
 
   // for a wildcard node, create constructor nodes with wildcards for all args.
   if (cand.as<PatternWildcardNode>()) {
-    TypeData td = mod->LookupDef(gtv);
+    TypeData td = mod->LookupTypeDef(gtv);
     // for each constructor add a candidate.
     Array<Pattern> ret;
     for (auto constructor : td->constructors) {
diff --git a/src/relay/pass/type_infer.cc b/src/relay/pass/type_infer.cc
index 78101bcf045a..23ed83cafc0f 100644
--- a/src/relay/pass/type_infer.cc
+++ b/src/relay/pass/type_infer.cc
@@ -574,7 +574,7 @@ class TypeInferencer : private ExprFunctor<Type(const Expr&)>,
     CHECK(mod_.defined())
       << "Cannot do type inference without a environment:"
       << c->name_hint;
-    TypeData td = mod_->LookupDef(c->belong_to);
+    TypeData td = mod_->LookupTypeDef(c->belong_to);
     std::vector<Type> types;
     for (const auto & t : td->type_vars) {
       types.push_back(t);
diff --git a/src/relay/pass/util.cc b/src/relay/pass/util.cc
index 3ad5dd11b7d8..577f492120c0 100644
--- a/src/relay/pass/util.cc
+++ b/src/relay/pass/util.cc
@@ -140,7 +140,7 @@ class TypeVarEVisitor : private ExprVisitor {
 
   void VisitExpr_(const ConstructorNode* cn) final {
     // for constructors, type vars will be bound in the module
-    auto data = mod_->LookupDef(cn->belong_to);
+    auto data = mod_->LookupTypeDef(cn->belong_to);
     for (const auto& tv : data->type_vars) {
       type_vars_.Insert(tv);
       bound_type_vars_.Insert(tv);