A compound word is formed by combining two or more smaller words together to create one word. For example, the word "football" is a compound word formed by combining the words "foot" and "ball". Similarly, "sunflower" is a compound word formed by combining the words "sun" and "flower". Compound words can be formed in different ways, such as by combining two nouns (e.g. "bookshelf"), a verb and a noun (e.g. "snowball"), or an adjective and a noun (e.g. "blackboard"). These words often have a different meaning than the individual words they are formed from. Compound words are important in language as they allow us to express complex ideas and concepts more efficiently.