Arch (?), n. [F. arche, fr. LL.
arca, for arcus. See Arc.] 1.
(Geom.) Any part of a curved line.
2. (Arch.) (a) Usually a
curved member made up of separate wedge-shaped solids, with the joints
between them disposed in the direction of the radii of the curve; used to
support the wall or other weight above an opening. In this sense arches are
segmental, round (i. e., semicircular), or
pointed. (b) A flat arch is a member
constructed of stones cut into wedges or other shapes so as to support each
other without rising in a curve.
☞ Scientifically considered, the arch is a means of spanning an
opening by resolving vertical pressure into horizontal or diagonal
thrust.
3. Any place covered by an arch; an archway; as, to
pass into the arch of a bridge.
4. Any curvature in the form of an arch; as, the
arch of the aorta. "Colors of the showery arch."
Milton.
Triumphal arch, a monumental structure resembling
an arched gateway, with one or more passages, erected to commemorate a
triumph.
Arch (ärch), a. [See Arch-,
pref.] 1. Chief; eminent; greatest;
principal.
The most arch act of piteous massacre.
Shak.
2. Cunning or sly; sportively mischievous; roguish;
as, an arch look, word, lad.
[He] spoke his request with so arch a leer.
Tatler.
Arch, n. [See Arch-, pref.]
A chief. [Obs.]
My worthy arch and patron comes to-night.
Shak.
Arch, v. t. [imp. & p. p.
Arched (?); p. pr. & vb. n. Arching.]
1. To cover with an arch or arches.
2. To form or bend into the shape of an
arch.
The horse arched his neck.
Charlesworth.
Arch, v. i. To form into an arch; to
curve.