The crossword solution for the term 'Prefix with CORTEX' is NEO, which is a three letter word. NEO is a prefix that means 'NEW' or 'recently formed'. It is often used in scientific terms to refer to something that is newly developed or recently discovered. In this case, it is being used as a prefix for the word 'CORTEX', which is the outer layer of the brain responsible for higher functions such as thought, memory, and language.