The basal or hinge joint of a maxilla (upper jaw part) in insects, or a hinge-like anatomical structure.
From Latin cardo meaning 'hinge,' from the root kar- relating to turning or twisting.
The cardo is so small you need a microscope to see it, but it's crucial for how insects eat—it's the tiny hinge that lets their jaws open and close, proving that evolution cares about engineering at every scale.
Complete word intelligence in one call. Free tier — 50 lookups/day.