What defines a compound word?

A compound word is defined as a word that is created by combining two or more smaller words into one. This process results in a new word that carries its own meaning, which often derives from the meanings of the original words. For example, "toothbrush" is a compound word formed from "tooth" and "brush." Each component contributes to the overall meaning, indicating an item used to clean teeth.

Understanding the concept of compound words is essential in the study of language as it demonstrates how linguistic elements can be creatively combined to form more complex ideas. In contrast, the other options describe different linguistic concepts that do not pertain specifically to compound words: a single word formed by joining letters does not capture the necessity of combining multiple words, while a grammatical term for a cluster of sounds refers more broadly to phonetics or perhaps syllables. Additionally, a single meaning word adopted from another language relates to loanwords, which do not involve the combination of words.