adjective. Of, relating to, or being a work that in style or form falls between the classical and popular genres.

adjective. Of, relating to, or being a classical composition that enjoys popular appeal because of modern elements.

adjective. Describing classical music of broad, popular appeal

adjective. Describing any of various approximations to either relativistic or quantum mechanical physics that retains elements of classical physics

"With musical settings that evoke Rachmaninoff by way of Debussy and sometimes inflected with J. S. Bach, she often moved beyond the realm of jazz into a semiclassical sphere, although the label semiclassical really doesn't suffice, because the music is improvised."

classical  neoclassical