Prefix: noun, verb

Cambridge Dictionary

As noun

"a letter or group of letters added to the beginning of a word to make a new word"

prefixCambridgeWords

Merriam-Webster

As verb

"to add a letter, number, or symbol at the beginning of a word or number"

As noun

"an affix attached to the beginning of a word, base, or phrase and serving to produce a derivative word or an inflectional form"

Definition of PREFIXMerriamWebster