IPA: /ˈbaɪwɜrd/
KK: /ˈbaɪˌwɜrd/
A word or phrase that is commonly used to represent a particular quality or idea, often becoming a symbol or example of something.
In the 1970s, polyester became a byword for poor fashion choices.
Byword → The word is formed from "by" (meaning near or beside) and "word" (from Old English "word", meaning a unit of language). Together, these parts suggest a term that is closely associated with or representative of something, often used to signify a common phrase or expression.
Think of a 'word' that is 'near' or closely associated with a particular idea or concept — that's what a byword represents.