Motif

noun

1. A recurring or dominant element; a theme.

   "See how the artist repeats the scroll motif throughout the work?"

2. A short melodic passage that is repeated in several parts of a work.
3. A decorative figure that is repeated in a design or pattern.
4. A decorative appliqué design or figure, as of lace or velvet, used in trimming.
5. The physical object or objects repeated at each point of a lattice. Usually atoms or molecules.