* A compound word: This is the most common answer. Compound words are formed by combining two words, like "rainbow" (rain + bow) or "firetruck" (fire + truck).
* A portmanteau: This is a word formed by blending two words together, like "smog" (smoke + fog) or "brunch" (breakfast + lunch).
* A phrase: Technically, any phrase is formed from two or more words.
So, depending on what you're looking for, the answer could be a compound word, a portmanteau, or any phrase.