Essential vs. non-essential material
SAT glossary · Course Foundations
Definition
Essential material identifies which thing is meant and takes no commas; non-essential material can be removed without changing which thing the sentence is about and takes a matched pair. Generalization: a proper noun is already fully identified, so what follows it is almost always non-essential.
Essential vs. non-essential material in plain English
Essential material is the part of a sentence that's REQUIRED to identify exactly which specific thing or person is being talked about — and it never gets set off with commas, because removing it would make the sentence's meaning unclear. Non-essential material is EXTRA information that could be deleted entirely without changing which specific thing the sentence is referring to — and it DOES need a matched pair of commas around it. A useful shortcut: once you've named someone using a proper noun (like a specific person's full name), that identification is already complete, so almost anything that comes after it is just extra (non-essential) detail, not identification.
Sign up free: all 157 SAT terms as flashcards, plus practice questions with full explanations →