The crossword solution for the term 'PREFIX WITH 'MODERN' OR 'SOUND'' is ULTRA. The prefix ULTRA- is derived from Latin and means 'BEYOND' or 'on the far side'. It is commonly used to describe something that is extreme, advanced, or modern. For example, an ULTRA-modern building would be a building that is extremely modern or advanced in design. Similarly, an ULTRA-sound is a type of sound that is BEYOND the range of human hearing.