1) A recurring subject, theme, or idea in art. For example, grainstacks appear frequently as motifs in the works of Claude Monet (1840- 1926).

Monet Grainstacks Sunset Snow EffectClaude Monet. Grainstacks, Sunset, Snow Effect. Oil on canvas. 1891. Art Institute of Chicago.

2) A distinct or separable element in the design of a pattern. web resource here.

Poiret parrot textilePaul Poiret.  Silk satin print with parrot motif.  Ca. 1911-1923. Metropolitan Museum of Art, New York.