The document discusses root words and their role in vocabulary development. It defines root words as the base or foundational part of a word and provides examples like "tele" and "vitamin." The document also explains that words in English are often formed by combining a prefix, root, and suffix. It provides root words like "bio," "hydro," and "geo" along with their meanings to help readers understand other words. In the end, it encourages learning roots to expand one's vocabulary and includes links for further root word reference.