The term 'FOOTPRINT FOSSIL' is a combination of two words, 'FOOTPRINT' and 'FOSSIL'. Footprints are the impressions left behind by an animal or person, while fossils are the remains or traces of ancient life. The crossword solution for this term is 'ichnite', which is a type of trace FOSSIL that is formed when an organism leaves an impression in sedimentary rock. Ichnites are typically found in the form of footprints, burrows, or other types of tracks.