Alliteration is a stylistic literary device identified by the repeated sound of the first letter in a series of multiple words, or the repetition of the same letter sounds in stressed syllables of a phrase. "Alliteration" is from the Latin word littera, meaning "letter of the alphabet", and the first known use of the word to refer to a literary device occurred around 1624. Alliteration narrowly refers to the repetition of a letter in any syllables that, according to the poem's meter, are stressed, as in James Thomson's verse "Come…dragging the lazy languid Line along". Another example is "Peter Piper picked a peck of pickled peppers".
Consonance is a broader literary device identified by the repetition of consonant sounds at any point in a word (e.g. coming home, hot foot). Alliteration is a special case of consonance where the repeated consonant sound is in the stressed syllable. Alliteration may also refer to the use of different but similar consonants, such as alliterating z with s, as does the author of Sir Gawain and the Green Knight, or as Anglo-Saxon (Old English) poets would alliterate hard/fricative g with soft g (the latter exemplified in some courses as the letter yogh – ȝ – pronounced like the y in yarrow or the j in Jotunheim); this is known as license.
There is one specialised form of alliteration called Symmetrical Alliteration. That is, alliteration containing parallelism. In this case, the phrase must have a pair of outside end words both starting with the same sound, and pairs of outside words also starting with matching sounds as one moves progressively closer to the centre. For example, "rust brown blazers rule", "purely and fundamentally for analytical purposes" or "fluoro colour co-ordination forever". Symmetrical alliteration is similar to palindromes in its use of symmetry.
Alliteration is used in the alliterative verse of Old English, Old Norse, Old High German, Old Saxon, and Old Irish. It was an important ingredient of the Sanskrit shlokas. Alliteration was used in Old English given names. This is evidenced by the unbroken series of 9th century kings of Wessex named Æthelwulf, Æthelbald, Æthelberht, and Æthelred. These were followed in the 10th century by their direct descendants Æthelstan and Æthelred II, who ruled as kings of England. The Anglo-Saxon saints Tancred, Torhtred and Tova provide a similar example, among .