diff --git a/spec/asyncapi.md b/spec/asyncapi.md
index e79588a17..de5d0e075 100644
--- a/spec/asyncapi.md
+++ b/spec/asyncapi.md
@@ -707,7 +707,7 @@ Field Name | Type | Description
externalDocs | [External Documentation Object](#externalDocumentationObject) | Additional external documentation for this operation.
bindings | [Operation Bindings Object](#operationBindingsObject) \| [Reference Object](#referenceObject) | A map where the keys describe the name of the protocol and the values describe protocol-specific definitions for the operation.
traits | [[Operation Trait Object](#operationTraitObject) | [Reference Object](#referenceObject) ] | A list of traits to apply to the operation object. Traits MUST be merged into the operation object using the [JSON Merge Patch](https://tools.ietf.org/html/rfc7386) algorithm in the same order they are defined here.
-message | [[Message Object](#messageObject) | [Reference Object](#referenceObject)] | A definition of the message that will be published or received on this channel. `oneOf` is allowed here to specify multiple messages, however, **a message MUST be valid only against one of the referenced message objects.**
+message | [Message Object](#messageObject) | [Reference Object](#referenceObject) | Map["oneOf", [[Message Object](#messageObject) | [Reference Object](#referenceObject)]] | A definition of the message that will be published or received by this operation. Map containing a single `oneOf` key is allowed here to specify multiple messages. However, **a message MUST be valid only against one of the message objects.**
This object can be extended with [Specification Extensions](#specificationExtensions).