Prefixes and suffixes are important elements in the structure of English words. They are types of affixes that are added to a base word or root to form new words or to change their grammatical function and meaning. A prefix is added before a root or base word, whereas a suffix is added after it. The study of prefixes and suffixes helps us understand word formation, vocabulary development, and the morphological structure of English. A prefix is a letter or group of letters placed at the beginning of a word. It generally changes the meaning of the original word without changing its grammatical category. For example, the prefix “un-” added to “happy” gives “unhappy,” meaning not happy. Similarly, “dis-” in “disagree” expresses the opposite meaning of “agree,” while “re-” in “rewrite” indicates repetition. Other common prefixes include “pre-” in “prepaid,” “mis-” in “misunderstand,” “im-” in “impossible,” “anti-” in “antivirus,” and “sub-” in “submarine.” Prefixes may express meanings such as negation, repetition, opposition, time, position, degree, or direction. Prefixes do not normally change the word class of the base word. For instance, “kind” and “unkind” are both adjectives, while “write” and