diff --git a/packages/squiggle-lang/__tests__/Reducer/Reducer_Peggy/Reducer_Peggy_Parse_type_test.res b/packages/squiggle-lang/__tests__/Reducer/Reducer_Peggy/Reducer_Peggy_Parse_type_test.res
index f1dcd4bc..4f7dabdc 100644
--- a/packages/squiggle-lang/__tests__/Reducer/Reducer_Peggy/Reducer_Peggy_Parse_type_test.res
+++ b/packages/squiggle-lang/__tests__/Reducer/Reducer_Peggy/Reducer_Peggy_Parse_type_test.res
@@ -20,7 +20,7 @@ describe("Peggy parse type", () => {
       "{(::$_typeOf_$ :f (::$_typeFunction_$ (::$_constructArray_$ (#number #number #number))))}",
     )
   })
-  describe("high priority modifier", () => {
+  describe("high priority contract", () => {
     testParse(
       "answer: number<-min<-max(100)|string",
       "{(::$_typeOf_$ :answer (::$_typeOr_$ (::$_constructArray_$ ((::$_typeModifier_max_$ (::$_typeModifier_min_$ #number) 100) #string))))}",
@@ -30,7 +30,7 @@ describe("Peggy parse type", () => {
       "{(::$_typeOf_$ :answer (::$_typeModifier_memberOf_$ #number (::$_constructArray_$ (1 3 5))))}",
     )
   })
-  describe("low priority modifier", () => {
+  describe("low priority contract", () => {
     testParse(
       "answer: number | string $ opaque",
       "{(::$_typeOf_$ :answer (::$_typeModifier_opaque_$ (::$_typeOr_$ (::$_constructArray_$ (#number #string)))))}",
@@ -70,7 +70,7 @@ describe("Peggy parse type", () => {
       "{(::$_typeOf_$ :answer (::$_typeModifier_opaque_$ (::$_typeOr_$ (::$_constructArray_$ (#number #string)))))}",
     )
   })
-  describe("squiggle expressions in type modifiers", () => {
+  describe("squiggle expressions in type contracts", () => {
     testParse(
       "odds1 = [1,3,5]; odds2 = [7, 9]; type odds = number<-memberOf(concat(odds1, odds2))",
       "{:odds1 = {(::$_constructArray_$ (1 3 5))}; :odds2 = {(::$_constructArray_$ (7 9))}; (::$_typeAlias_$ #odds (::$_typeModifier_memberOf_$ #number (::concat :odds1 :odds2)))}",
diff --git a/packages/squiggle-lang/__tests__/Reducer/Reducer_Peggy/Reducer_Peggy_ToExpression_type_test.res b/packages/squiggle-lang/__tests__/Reducer/Reducer_Peggy/Reducer_Peggy_ToExpression_type_test.res
index 12d2d62b..9849adb0 100644
--- a/packages/squiggle-lang/__tests__/Reducer/Reducer_Peggy/Reducer_Peggy_ToExpression_type_test.res
+++ b/packages/squiggle-lang/__tests__/Reducer/Reducer_Peggy/Reducer_Peggy_ToExpression_type_test.res
@@ -40,7 +40,7 @@ describe("Peggy Types to Expression", () => {
       (),
     )
   })
-  describe("high priority modifier", () => {
+  describe("high priority contract", () => {
     testToExpression(
       "answer: number<-min(1)<-max(100)|string",
       "{(:$_typeOf_$ :answer (:$_typeOr_$ (:$_constructArray_$ ((:$_typeModifier_max_$ (:$_typeModifier_min_$ #number 1) 100) #string))))}",
@@ -78,7 +78,7 @@ describe("Peggy Types to Expression", () => {
       (),
     )
   })
-  describe("low priority modifier", () => {
+  describe("low priority contract", () => {
     testToExpression(
       "answer: number | string $ opaque",
       "{(:$_typeOf_$ :answer (:$_typeModifier_opaque_$ (:$_typeOr_$ (:$_constructArray_$ (#number #string)))))}",
@@ -86,7 +86,7 @@ describe("Peggy Types to Expression", () => {
       (),
     )
   })
-  describe("squiggle expressions in type modifiers", () => {
+  describe("squiggle expressions in type contracts", () => {
     testToExpression(
       "odds1 = [1,3,5]; odds2 = [7, 9]; type odds = number<-memberOf(concat(odds1, odds2))",
       "{(:$_let_$ :odds1 {(:$_constructArray_$ (1 3 5))}); (:$_let_$ :odds2 {(:$_constructArray_$ (7 9))}); (:$_typeAlias_$ #odds (:$_typeModifier_memberOf_$ #number (:concat :odds1 :odds2)))}",
diff --git a/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_Modifiers.res b/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_Contracts.res
similarity index 90%
rename from packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_Modifiers.res
rename to packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_Contracts.res
index 457e97d8..7b68f178 100644
--- a/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_Modifiers.res
+++ b/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_Contracts.res
@@ -41,10 +41,10 @@ let checkModifier = (
   }
 
 let checkModifiers = (
-  modifiers: Belt.Map.String.t<InternalExpressionValue.t>,
+  contracts: Belt.Map.String.t<InternalExpressionValue.t>,
   aValue: InternalExpressionValue.t,
 ): bool => {
-  modifiers->Belt.Map.String.reduce(true, (acc, key, modifierArg) =>
+  contracts->Belt.Map.String.reduce(true, (acc, key, modifierArg) =>
     switch acc {
     | true => checkModifier(key, modifierArg, aValue)
     | _ => acc
diff --git a/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_T.res b/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_T.res
index d8011d23..511fe815 100644
--- a/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_T.res
+++ b/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_T.res
@@ -3,7 +3,7 @@ open InternalExpressionValue
 
 type rec iType =
   | ItTypeIdentifier(string)
-  | ItModifiedType({modifiedType: iType, modifiers: Belt.Map.String.t<InternalExpressionValue.t>})
+  | ItModifiedType({modifiedType: iType, contracts: Belt.Map.String.t<InternalExpressionValue.t>})
   | ItTypeOr({typeOr: array<iType>})
   | ItTypeFunction({inputs: array<iType>, output: iType})
   | ItTypeArray({element: iType})
@@ -16,8 +16,8 @@ type typeErrorValue = TypeMismatch(t, InternalExpressionValue.t)
 let rec toString = (t: t): string => {
   switch t {
   | ItTypeIdentifier(s) => s
-  | ItModifiedType({modifiedType, modifiers}) =>
-    `${toString(modifiedType)}${modifiers->Belt.Map.String.reduce("", (acc, k, v) =>
+  | ItModifiedType({modifiedType, contracts}) =>
+    `${toString(modifiedType)}${contracts->Belt.Map.String.reduce("", (acc, k, v) =>
         Js.String2.concatMany(acc, ["<-", k, "(", InternalExpressionValue.toString(v), ")"])
       )}`
   | ItTypeOr({typeOr}) => `(${Js.Array2.map(typeOr, toString)->Js.Array2.joinWith(" | ")})`
@@ -82,7 +82,7 @@ let rec fromTypeMap = typeMap => {
     default,
   )
 
-  let modifiers =
+  let contracts =
     typeMap->Belt.Map.String.keep((k, _v) => ["min", "max", "memberOf"]->Js.Array2.includes(k))
 
   let makeIt = switch evTypeTag {
@@ -96,9 +96,9 @@ let rec fromTypeMap = typeMap => {
   | _ => raise(Reducer_Exception.ImpossibleException("Reducer_Type_T-evTypeTag"))
   }
 
-  Belt.Map.String.isEmpty(modifiers)
+  Belt.Map.String.isEmpty(contracts)
     ? makeIt
-    : ItModifiedType({modifiedType: makeIt, modifiers: modifiers})
+    : ItModifiedType({modifiedType: makeIt, contracts: contracts})
 }
 
 and fromIEvValue = (ievValue: InternalExpressionValue.t): iType =>
diff --git a/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_TypeChecker.res b/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_TypeChecker.res
index 2778d3e4..e4336df5 100644
--- a/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_TypeChecker.res
+++ b/packages/squiggle-lang/src/rescript/Reducer/Reducer_Type/Reducer_Type_TypeChecker.res
@@ -1,7 +1,7 @@
 module ExpressionT = Reducer_Expression_T
 module InternalExpressionValue = ReducerInterface_InternalExpressionValue
 module T = Reducer_Type_T
-module TypeModifiers = Reducer_Type_Modifiers
+module TypeContracts = Reducer_Type_Contracts
 open InternalExpressionValue
 
 let rec isITypeOf = (anIType: T.iType, aValue): result<bool, T.typeErrorValue> => {
@@ -92,11 +92,11 @@ let rec isITypeOf = (anIType: T.iType, aValue): result<bool, T.typeErrorValue> =
   let caseModifiedType = (
     anIType: T.iType,
     modifiedType: T.iType,
-    modifiers: Belt.Map.String.t<InternalExpressionValue.t>,
+    contracts: Belt.Map.String.t<InternalExpressionValue.t>,
     aValue: InternalExpressionValue.t,
   ) => {
     isITypeOf(modifiedType, aValue)->Belt.Result.flatMap(_result => {
-      if TypeModifiers.checkModifiers(modifiers, aValue) {
+      if TypeContracts.checkModifiers(contracts, aValue) {
         Ok(true)
       } else {
         T.TypeMismatch(anIType, aValue)->Error
@@ -106,8 +106,8 @@ let rec isITypeOf = (anIType: T.iType, aValue): result<bool, T.typeErrorValue> =
 
   switch anIType {
   | ItTypeIdentifier(name) => caseTypeIdentifier(name, aValue)
-  | ItModifiedType({modifiedType, modifiers}) =>
-    caseModifiedType(anIType, modifiedType, modifiers, aValue) //{modifiedType: iType, modifiers: Belt.Map.String.t<InternalExpressionValue.t>}
+  | ItModifiedType({modifiedType, contracts}) =>
+    caseModifiedType(anIType, modifiedType, contracts, aValue) //{modifiedType: iType, contracts: Belt.Map.String.t<InternalExpressionValue.t>}
   | ItTypeOr({typeOr}) => caseOr(anIType, typeOr, aValue)
   | ItTypeFunction(_) =>
     raise(