What term refers to parts of words added at the beginning or end of a word?

The term that refers to parts of words added at the beginning or end of a word is "affix." An affix can take the form of a prefix, which is added to the beginning of a base word, or a suffix, which is added to the end of a base word. Affixes are crucial in changing the meaning of the base word or in forming different grammatical forms, such as different tenses or parts of speech. For example, adding "un-" to the base word "happy" creates "unhappy," changing its meaning.

In contrast, a base word is the main part of a word that carries meaning and can stand alone, while a blend refers to a combination of two or more words or sounds to form a new word, and alliteration is a poetic device involving the repetition of the same initial consonant sound in a sequence of words.