Any part of a curved line.
- A structure, especially one of masonry, forming the curved, pointed, or flat upper edge of an open space and supporting the weight above it, as in a bridge or doorway.
- A structure, such as a freestanding monument, shaped like an inverted U.
- A curve with the ends down and the middle up: the arch of a raised eyebrow.
- Anatomy An organ or structure having a curved or bowlike appearance, especially either of two arched sections of the bony structure of the foot.
- To provide with an arch: arch a passageway.
- To cause to form an arch or similar curve.
- To bend backward: The dancers alternately arched and hunched their backs.
- To span: "the rude bridge that arched the flood” ( Ralph Waldo Emerson).
- To form an arch or archlike curve: The high fly ball arched toward the stands.
- Chief; principal: their arch foe.
- Mischievous; roguish: an arch glance.