Definify.com
Webster 1913 Edition
Aperture
1.
The act of opening.
[Obs.]
2.
An opening; an open space; a gap, cleft, or chasm; a passage perforated; a hole;
as, an
. aperture
in a wallAn
aperture
between the mountains. Gilpin.
The back
aperture
of the nostrils. Owen.
3.
(Opt.)
The diameter of the exposed part of the object glass of a telescope or other optical instrument;
as, a telescope of four-inch
. aperture
☞ The aperture of microscopes is often expressed in degrees, called also the angular aperture, which signifies the angular breadth of the pencil of light which the instrument transmits from the object or point viewed; as, a microscope of 100° aperture.
Webster 1828 Edition
Aperture
AP'ERTURE
, n.1.
The act of opening; more generally, an opening; a gap, cleft or chasm; a passage perforated; a hole through any solid substance.2.
An opening of meaning; explanation. [Not used.]3.
In geometry, the space between two right lines, forming an angle.