An appositive renames the noun beside it, so in a diagram it sits beside that noun, in parentheses, on the same line. Its own modifiers hang under it. This builds on Diagrams: Complements.
Some words are not part of the sentence’s frame at all: interjections (wow, oh) and nouns of direct address (the name of the person spoken to). Each sits on its own short line above the baseline.
Key idea
Renames the noun? Beside it, in parentheses. Not part of the sentence’s frame (interjection, direct address)? On a line above.
Why it works
An appositive is the same thing as its noun, so it shares the noun’s place on the line. Interjections and names in direct address do no job inside the sentence, so they sit apart, just as commas set them apart in writing.
Worked example: A name in direct address
Diagram “Leo, close the window.”
- A command: the subject is (you).
- Baseline: (you) | close | window, with the under window.
- Leo is the person spoken to: on a short line above the baseline.
Answer: Leo above; (you) | close | window
Common mistake
Hanging an appositive under the noun as if it were an adjective. An appositive doesn’t describe the noun; it renames it, so it stands beside it.
Reed and Kellogg called an appositive an “explanatory modifier” and wrote it “enclosed in curves” (parentheses), as here.