What Is an Echo Word?

In linguistics and composition, the term echo word has more than one meaning:

1. An echo word is a word or phrase (such as buzz and cock a doodle doo) that imitates the sound associated with the object or action it refers to: an onomatope. Also called an echoic word. 
2. An echo word is a word or phrase (such as shilly shally and click and clack) that contains two identical or very similar parts: a reduplicative.
3. An echo word is a word or phrase that recurs in a sentence or paragraph.

Examples and Observations

• "Sound alone is the basis of a limited number of words, called echoic or onomatopoeic, like bang, burp, splash, tinkle, bobwhite, and cuckoo. Words that are actually imitative of sound, like meow, bowwow, and vroom--though these differ from language to language--can be distinguished from those like bump and flick, which are called symbolic. Symbolic words regularly come in sets that rhyme (bump, lump, clump, hump) or alliterate (flick, flash, flip, flop) and derive their symbolic meaning at least in part from other members of their sound-alike sets. Both imitative and symbolic words frequently show doubling, sometimes with slight variation, as in bowwow, choo-choo, and peewee."
  (John Algeo and Thomas Pyles, The Origins and Development of the English Language, 5th ed. Thomson Wadsworth, 2005)

• "Repetitions help to echo keywords, to emphasize important ideas or main points, to unify sentences, or to develop coherence among sentences. Skillful repetitions of important words or phrases create 'echoes' in the reader's mind: they emphasize and point out key ideas. You can use these 'echo words' in different sentences--even in different paragraphs--to help 'hook' your ideas together...
• "[E]cho words may come any place in the sentence: with the subjects or the verbs, with the objects or the complements, with prepositions or other parts of speech. You need not always repeat the word exactly; think of other forms the word may take, such as freak, freakiness, freakishness (nouns), freaking (participle), freaky and freakish (adjectives), and freakishly and freakily (adverbs)." (Ann Longknife and K. D. Sullivan, The Art of Styling Sentences, 4th ed. Barron's, 2002)

Echo-Pairs 

• "Echo-words are crucially different from straight reduplicated words in that they have rules sensitive to the reduplicated configuration, 'detaching melodic elements from the affixal skeleton' and replacing them with an invariant onset (McCarthy and Prince 1986, 86). This accounts for the ban on auto-reduplication of echo-words themselves. Yiddishized English shm-initial words undergoing echo-pairing (such as shmaltz) have to be echo-paired with something else (usuall shp-: shpaltz) or else with nothing (no echo-pair can be formed), but certainly not with a direct repeat (**shmaltz-shmaltz is disallowed)." ( Mark R. V. Southern, Contagious Couplings: Transmission of Expressives in Yiddish Echo Phrases. Praeger, 2005)