undercross

Definitions

1. A passage or underpass where a roadway, railway, or infrastructure crosses under another.
2. The strand or segment in a knot diagram that passes beneath another at a crossing; i.e., the under‑crossing strand in a knot projection. As distinguished from the overcrossing or over‑strand in knot projections

Examples

“The whole of the undercross is perfect, excepting the bases of the outer columns, and forms a fine superstructure of gigantic support⟳ to the light⟳ and delicate parts above.”

“If we arrive⟳ at an undercross, then we move⟳ the branch of the overcross over the rest⟳ of the knot up to the end⟳ of K.”

CEFR level