The race car decor in your room, the refrain of a song, the idea or object that keeps popping up in a story — these are all motifs, reoccurring elements that move throughout and shape music, art and novels.
This French import is related to the Latin verb movere which means "to move." Think about a pattern or design that moves throughout something when you hear motif. Have you ever been to a restaurant with a tropical or Wild West motif? Do you like dresses with a floral motif? In novels, a motif can be a recurring idea like revenge or an object that symbolizes an idea. A character might notice shadows throughout a story which symbolize his dark past.