diff --git a/implementations/javascript/packages/schema/src/reader.ts b/implementations/javascript/packages/schema/src/reader.ts
index 233b36c..76e05ea 100644
--- a/implementations/javascript/packages/schema/src/reader.ts
+++ b/implementations/javascript/packages/schema/src/reader.ts
@@ -61,7 +61,7 @@ export function readSchema(source: string,
 {
     const checked = checkSchema(parseSchema(_readSchema(source, options), options ?? {}));
     if (checked.ok) return checked.schema;
-    throw new Error(`Schema does not specify a bijection:\n` +
+    throw new Error(`Schema is not invertible:\n` +
         checked.problems.map(c => ' - ' + c).join('\n'));
 }
 
diff --git a/implementations/javascript/packages/schema/test/checker.test.ts b/implementations/javascript/packages/schema/test/checker.test.ts
index 583355f..35920c5 100644
--- a/implementations/javascript/packages/schema/test/checker.test.ts
+++ b/implementations/javascript/packages/schema/test/checker.test.ts
@@ -3,17 +3,17 @@ import { Meta, readSchema } from '../src/index';
 import './test-utils';
 
 describe('checker', () => {
-    describe('simplest non-bijection tests', () => {
-        it('passes simple non-bijection test', () => {
+    describe('simplest invertibility tests', () => {
+        it('passes simple invertibility test', () => {
             expect(readSchema('version 1 . A = <a @x string @y symbol> .')).not.toBeNull();
         });
-        it('passes non-bijection check for literal field', () => {
+        it('passes invertibility check for literal field', () => {
             expect(readSchema('version 1 . A = <a "string" @y symbol> .')).not.toBeNull();
         });
-        it('detects non-bijection for string field', () => {
+        it('detects non-invertibility for string field', () => {
             expect(() => readSchema('version 1 . A = <a string @y symbol> .')).toThrow(/item 0 of fields of A/);
         });
-        it('detects non-bijection for symbol field', () => {
+        it('detects non-invertibility for symbol field', () => {
             expect(() => readSchema('version 1 . A = <a @x string symbol> .')).toThrow(/item 1 of fields of A/);
         });
         it('is OK with no names in simple seqof', () => {
@@ -35,7 +35,7 @@ describe('checker', () => {
                                 <tuple* [<named a <atom String>>, <named b <atom String>>]
                                         <named extra <seqof any>>>>}}>`).next());
         });
-        it('non-bijection tail', () => {
+        it('non-invertibility tail', () => {
             expect(() => readSchema(
                 'version 1 . ExtensibleRecord = <foo @a string @b string any ...>.'))
                 .toThrow(/tail of fields of ExtensibleRecord/);
diff --git a/implementations/racket/preserves/preserves-schema/checker.rkt b/implementations/racket/preserves/preserves-schema/checker.rkt
index 5c92bd5..2065018 100644
--- a/implementations/racket/preserves/preserves-schema/checker.rkt
+++ b/implementations/racket/preserves/preserves-schema/checker.rkt
@@ -25,7 +25,7 @@
       [(SimplePattern-lit _)
        (void)]
       [(? SimplePattern?)
-       (when (not value-available?) (problem! context "non-bijection"))]
+       (when (not value-available?) (problem! context "necessary information not captured"))]
       [(CompoundPattern-rec l f)
        (check-named-pattern (cons "label" context) scope l)
        (check-named-pattern (cons "fields" context) scope f)]