Texture often refers to the overall "thickness" or "thinness" of piano writing. A few groups of octaves and fifths, especially if slow, would be a thin texture. A fast four-part dissonant fugue would be a thick texture. You could more loosely describe texture as the atmospheric effect created by the speed, density and layering of notes, for example: fluid, brusque, heavy, gloomy, sparkling, or buttery smooth. Some people use texture as a technical term to refer to the number of voices in a piece, so they're looking for homophonic, polyphonic etc.