Noun
formation of a word by means of a prefix
Source: WordNetAffixations, the linguistic process speakers use form different words by adding morphemes (affixes) at the beginning (prefixation), the middle (infixation) or the end (suffixation) of words. Source: Internet
Perfective verbs can be usually formed from imperfective ones by suffixation or prefixation, but the resultant verb often deviates in meaning from the original. Source: Internet