The crossword solution for the term 'prefix with -nautic' is AERO, which is a 4-letter word. AERO is a prefix derived from the Greek word 'aer', meaning air or atmosphere. It is commonly used in combination with other words to form compound words related to air or atmosphere, such as aeronautics, aerodynamics, and aerostatics. The prefix -nautic is also derived from the Greek word 'nautes', meaning sailor or navigator. When combined with AERO, it forms the compound word 'aeronautic', which refers to the science of navigation through the air.