When You Should Hyphenate, Open, or Close a Compound Word ...
https://writingcooperative.com/when-you-should-hyphenate-open-or-close...02.08.2020 · Common compound words. But first, let’s consider some common compound words. Simply put, compound words are formed when two or more separate words are combined. The first type of compound words taught to very young students are closed (with no space or hyphen), as in airplane, birthday, campfire, daydream, earlobe, firefly, etc.