Alliteration is the repetition of consonant sounds, particularly at the beginnings of words. 

Alliteration describes multiple words grouped together that contain the same first consonant sound. Alliteration is used in common speech and all forms of literature, but it is especially prominent in poetry, which places emphasis on sound and the sound of words. Alliteration is also commonly used in marketing materials and nursery rhymes because of the pleasing and memorable sounds it creates. 

William Shakespeare uses alliteration in “When to the sessions of sweet silent thought (Sonnet 30).” 

When to the sessions of sweet silent thought
I summon up remembrance of things past,
I sigh the lack of many a thing I sought 

The words “sessions,” “sweet,” “silent,” “summon,” “sigh,” and “sought” all begin with the same beginning consonant sound and occur close together in the first three lines of the poem. Other poems that use alliteration include “Birches” by Robert Frost, “Pied Beauty” by Gerard Manley Hopkins, “Shainadas” by Brandon Som, and “The Sound of Their Names” by Ellen Bass.