noun (n)

• use of the same consonant at the beginning of each stressed syllable in a line of verse(noun.communication)

  Synonym:
  beginning rhyme, head rhyme, initial rhyme
  

  source: wordnet30
• The repetition of the same letter at the beginning of two or more words immediately succeeding each other, or at short intervals; as in the following lines: -(noun)

  source: webster1913