Are compound nouns capitalized? I'm not 100% sure, but are they or are they not capitalized?
A compound noun is one that is built on two or more smaller words. For example, "playground" is a compound noun.
Compound nouns are not, as a rule, capitalized.
What are, as a rule, capitalized are proper nouns, which are nouns that are names of people, places and things like that. Here's a sentence with some proper nouns: "Whenever Bob [proper noun] is in Seattle [proper noun], he visits the Seattle Space Needle [proper noun]." And quick note, the word "whenever" is a compound noun but was only capitalized because it was the first word in the sentence.