diff --git a/docs/USING_PRO.md b/docs/USING_PRO.md
index af4f1986c5..92c478094f 100644
--- a/docs/USING_PRO.md
+++ b/docs/USING_PRO.md
@@ -362,7 +362,7 @@ The renderer function has access to the parser in the `this` object, which can b
**Example:** Add a custom syntax to generate `
` description lists.
``` js
-const descriptionlist = {
+const descriptionList = {
name: 'descriptionList',
level: 'block', // Is this a block-level or inline-level tokenizer?
start(src) { return src.match(/:[^:\n]/)?.index; }, // Hint to Marked.js to stop and check for a match
@@ -413,7 +413,7 @@ function walkTokens(token) { // Post-processing on the co
token.tokens = this.Lexer.lexInline(token.text)
}
}
-marked.use({ extensions: [descriptionlist, description], walkTokens });
+marked.use({ extensions: [descriptionList, description], walkTokens });
// EQUIVALENT TO: