How to sign: any spatial attributes (especially as defined by outline)
"he could barely make out their shapes through the smoke";
Similiar / Same: shape, contour, conformation, form
Categories: spatiality, spatial property
Within this category: angularity, concavity, convexity, crookedness, curvature, dullness, lobularity, narrowing, roundness, sharpness, straightness, stratification, topography