Which term defines the consonant sounds preceding or following a vowel in a syllable?

The term that accurately defines the consonant sounds preceding or following a vowel in a syllable is "blend." In phonics, blends refer specifically to groups of two or three consonant sounds that are closely joined together, such that each sound is still heard distinctly. For example, in the word "street," the "str" sound is a blend that occurs before the vowel "e."

Other terms do not fit this definition. An affix refers to a prefix or suffix attached to a base word to modify its meaning, which does not describe the sound structure surrounding a vowel. A base word is the main part of a word without any prefixes or suffixes added, focusing more on the core meaning rather than phonetic structure. Alliteration involves the repetition of initial consonant sounds in a sequence of words, which is a stylistic device rather than a description of sounds around a vowel within a syllable. Thus, "blend" is the correct choice to describe the consonants in relation to the vowel in syllable formation.