Oxford English Dictionary
1. gen. The commencing of two or more words in close connection, with the same letter, or rather the same sound
2. The commencement of certain accented syllables in a verse with the same consonant or consonantal group, or with different vowel sounds, which constituted the structure of versification in Old English and the Teutonic languages generally.
Examples from poetry and literature
"The soul selects her own society." (Emily Dickinson)
"A moist young moon hung above the mist of a neighboring meadow." (Vladimir Nabokov, Conclusive Evidence, 1951)
From Poe's The Raven:
Once upon a midnight dreary while I pondered weak and weary . . .
. . . that rare and radiant maiden . . .
Deep into that darkness peering, long I stood there
Carrie's cat clawed her couch, creating chaos.
Fredís friends fried Fritos for Fridayís food.
Tim took tons of tools to make toys for tots.
"You'll never put a better bit of butter on your knife."
(advertising slogan for Country Life butter)