Schema: parentItem
Schema: parentItem Example Markup
The following are examples of markup written in json+ld that include the correct usage for Schema: parentItem.
Comment
Comment JSON-LD example for a blog post reply. Covers downvoteCount, upvoteCount, parentItem, and sharedContent (the 4 properties unique to Comment), plus how to structure comment threads with nested replies.
Question
Question JSON-LD example for Q&A, FAQ, and quiz content. Comment subtype carrying acceptedAnswer, suggestedAnswer, answerCount, eduQuestionType. The node Google reads for Q&A rich results and quiz LearningResource pages.
Answer
Answer JSON-LD example — Comment subtype with answerExplanation and parentItem. Half of the Q&A rich-result pair with Question.