The term 'PREFIX WITH RED OR STRUCTURE' can be solved by the crossword solution INFRA. The word INFRA is a prefix that means 'BELOW' or 'BENEATH'. It is often used in combination with other words to form terms related to structure, such as infrastructure or infrastructural. It can also be used with the word 'RED' to form the term INFRA-RED, which refers to electromagnetic radiation with a wavelength just beyond the visible spectrum.