The term 'EXTREME SORT' can be broken down into two words: 'EXTREME' and 'SORT'. 'EXTREME' is an adjective that means 'very great in degree' or 'far beyond the norm'. 'SORT' is a verb that means 'to arrange in a particular order'. Therefore, the term 'EXTREME SORT' can be defined as arranging something in a very specific order. The crossword solution for this term is 'ULTRA', which is an adjective meaning 'going beyond what is usual or ordinary; very EXTREME or intense'.