The crossword solution for the term 'PREFIX 'WITHIN'' is INTRA, which is a five-letter word. Intra is a Latin prefix meaning 'WITHIN' or 'INSIDE' and is used to form words that refer to something that is contained WITHIN a larger entity. For example, the word 'intramural' refers to activities that take place WITHIN a particular group or organization. Similarly, the word 'intranet' refers to a private network that is contained WITHIN an organization.