The repetition of identical or similar sounds at the beginning of words or in stressed syllables, as in Modern alliteration is predominantly consonantal; certain literary traditions, such as Old English verse, also alliterate using vowel sounds.
Repetition of an initial sound, usually of a consonant or cluster, in two or more words of a phrase, line of poetry, etc. (Ex.: “What a tale of terror now their turbulency tells!”)
Webster's New World
The repetition of consonants at the beginning of two or more words immediately succeeding each other, or at short intervals.
The recurrence of the same letter in accented parts of words, as in Anglo-Saxon alliterative meter.