(ärch) noun
1. A curved structure spanning an opening, formed of wedge-shaped parts resting on supports at the two extremities.
2. Any similar structure or object; an archway.
3. The form of an arch; a bowlike curve.
4. Mech. The height within the curve of an arched body, as through the central portion of a leaf spring.
5. Aeron. a The curve of a surface from front to rear, b A curved wing tip.
6. Anat. A curved or archlike part: the dental arch.
7. One of the major patterns into which all fingerprints are divided: subclassed as plain, tented, and exceptional.
—v.t.
1. To cause to form an arch or arches.
2. To furnish with an arch or arches.
3. To span; extend over, as an arch.
—v.i.
4. To form an arch or arches. [<OF arche <Med. L. arca <L arcus bow, arch. Doublet of ARC.]
TYPES OF ARCHES

(ärch) adjective
1. Cunning; roguish; sly; coy.
2. Most eminent; chief. [<ARCH-]
—arch′ly adverb
—arch′ness noun

1. Chief; principal: archchancellor.
2. Very great; extreme: archknave. Also archi-, as in archidiaconal. [OE arce-, erce- <L arch-, arche-, archi- <Gk. archos ruler]