cierto means true if it appears after a noun?

Question

The lesson states the following:

Cierto can also mean "verdadero/seguro" (true/truthful/sure/reliable). In this case, used with a noun, the adjective cierto is placed after the noun. For example:

¿Es cierto lo que dijo Marcos ayer?Is it true what Marcos said yesterday?

In the example above cierto is following a verb. Am I missing something?

Silvia Piriz · Accepted Answer

Hola Devin P.
Great observation! You're right that in the sentence ¿Es cierto lo que dijo Marcos ayer?, cierto isn’t following a noun but rather a verb.
The key here is that cierto is functioning as a predicative adjective, meaning it's used with the verb ser (in this case es) to describe the entire clause that follows (lo que dijo Marcos ayer). So es cierto translates as “it is true”.
This is different from when cierto is used after a noun within a noun phrase, like in una historia cierta (“a true story”), where it directly modifies the noun.
So the rule about cierto meaning “true” when it comes after a noun applies to noun phrases, not to predicative structures like this one.
You're not missing anything, just spotting a different use of the word!
Saludos
Silvia