2pre·fix 
/ˌpri:ˈfɪks/ verb
pre·fix·es; pre·fixed; pre·fix·ing /ˌpri:ˈfɪks/ verb [+ obj] : to add a letter, number, or symbol at the beginning of a word or number
▪ Prefix “un” to “do” to form the word “undo.” ▪ The cost of the item was prefixed by/with a dollar sign.
▪ Prefix “un” to “do” to form the word “undo.” ▪ The cost of the item was prefixed by/with a dollar sign.
