The term 'autumnal' can be described by the crossword solutions ocher (5 letters), OPAL (4 letters), and Leonid (6 letters). Ocher is a yellow-brown color that is often associated with the changing of the leaves in autumn. OPAL is a gemstone that is known for its rainbow-like colors, which can be seen in the changing leaves of autumn. Leonid is a meteor shower that occurs every November, which is the peak of the autumn season.