cross-section - A representation of an object as it would appear if cut by an intersecting plane, so that the internal structure is displayed.
Also called a "section."
Examples of cross-sections of objects from nature:
Cross-section of a tree trunk. See wood.
Cross-section of a red cabbage.
Cross-section of the human eye. And another one. See sight.
Variations on this approach to illustrating the relationships between internal and external forms are "cutaway" and "exploded" views.
Examples of cross-section views from art:
English, from the Encyclopedia Britannica, 1897: Four views of the Roman Pantheon, 118 CE: front elevation, flank elevation, cross-section, and floor plan, late 19th century, engraving. The cross-section is the image in the lower-left. See elevation, plan, and pantheon.
Leonardo da Vinci (Italian, 1452-1519), Skull, 1489. This is a lateral cross-section view of a human skull — the left half of the calvaria has been removed to expose the interior. See anatomy, drawing, Renaissance, and study.
Also see architecture, bird's-eye view, didactic, drawing, elevation, plan, and point of view.