quadrant 音标拼音: [kw'ɑdrənt]
n . 四分圆,象限,四分仪
四分圆,象限,四分仪
quadrant 象限
QUAD quadrant 象限
quadrant n 1 :
a quarter of the circumference of a circle [
synonym :
{
quadrant }, {
quarter -
circle }]
2 :
any of the four areas into which a plane is divided by two orthogonal coordinate axes 3 :
the area enclosed by two perpendicular radii of a circle 4 :
a measuring instrument for measuring altitude of heavenly bodies Octant \
Oc "
tant \,
n . [
L .
octans , -
antis .
fr .
octo eight .
See {
Octave }.]
1 . (
Geom .)
The eighth part of a circle ;
an arc of 45 degrees .
[
1913 Webster ]
2 . (
Astron . &
Astrol .)
The position or aspect of a heavenly body ,
as the moon or a planet ,
when half way between conjunction ,
or opposition ,
and quadrature ,
or distant from another body 45 degrees .
[
1913 Webster ]
3 .
An instrument for measuring angles (
generally called a {
quadrant }),
having an arc which measures up to 9O [
deg ],
but being itself the eighth part of a circle .
Cf .
{
Sextant }.
[
1913 Webster ]
4 . (
Math . &
Crystallog .)
One of the eight parts into which a space is divided by three coordinate planes .
[
1913 Webster ]
Quadrant \
Quad "
rant \,
n . [
L .
quadrans , -
antis ,
a fourth part ,
a fourth of a whole ,
fr .
quattuor four :
cf .
F .
quadrant ,
cadran .
See {
Four },
and cf . {
Cadrans }.]
1 .
The fourth part ;
the quarter . [
Obs .] --
Sir T .
Browne .
[
1913 Webster ]
2 . (
Geom .)
The quarter of a circle ,
or of the circumference of a circle ,
an arc of 90 [
deg ],
or one subtending a right angle at the center .
[
1913 Webster ]
3 . (
Anal . (
Geom .)
One of the four parts into which a plane is divided by the coordinate axes .
The upper right -
hand part is the first quadrant ;
the upper left -
hand part the second ;
the lower left -
hand part the third ;
and the lower right -
hand part the fourth quadrant .
[
1913 Webster ]
4 .
An instrument for measuring altitudes ,
variously constructed and mounted for different specific uses in astronomy ,
surveying ,
gunnery ,
etc .,
consisting commonly of a graduated arc of 90 [
deg ],
with an index or vernier ,
and either plain or telescopic sights ,
and usually having a plumb line or spirit level for fixing the vertical or horizontal direction .
[
1913 Webster ]
{
Gunner '
s quadrant },
an instrument consisting of a graduated limb ,
with a plumb line or spirit level ,
and an arm by which it is applied to a cannon or mortar in adjusting it to the elevation required for attaining the desired range .
{
Gunter '
s quadrant }.
See {
Gunter '
s quadrant },
in the Vocabulary .
{
Hadley '
s quadrant },
a hand instrument used chiefly at sea to measure the altitude of the sun or other celestial body in ascertaining the vessel '
s position .
It consists of a frame in the form of an octant having a graduated scale upon its arc ,
and an index arm ,
or alidade pivoted at its apex .
Mirrors ,
called the index glass and the horizon glass ,
are fixed one upon the index arm and the other upon one side of the frame ,
respectively .
When the instrument is held upright ,
the index arm may be swung so that the index glass will reflect an image of the sun upon the horizon glass ,
and when the reflected image of the sun coincides ,
to the observer '
s eye ,
with the horizon as seen directly through an opening at the side of the horizon glass ,
the index shows the sun '
s altitude upon the scale ; --
more properly ,
but less commonly ,
called an octant .
{
Quadrant of altitude },
an appendage of the artificial globe ,
consisting of a slip of brass of the length of a quadrant of one of the great circles of the globe ,
and graduated .
It may be fitted to the meridian ,
and being movable round to all points of the horizon ,
serves as a scale in measuring altitudes ,
azimuths ,
etc .
[
1913 Webster ]
51 Moby Thesaurus words for "
quadrant ":
adjunct ,
astrolabe ,
azimuth circle ,
azimuth compass ,
bevel ,
bevel protractor ,
bevel square ,
clinometer ,
component ,
contingent ,
crescent ,
cross section ,
detachment ,
detail ,
division ,
dole ,
fraction ,
goniometer ,
graphometer ,
half circle ,
hemicycle ,
installment ,
item ,
pantometer ,
parcel ,
part ,
particular ,
percentage ,
portion ,
protractor ,
quarter ,
quota ,
radiogoniometer ,
random sample ,
remainder ,
sample ,
sampling ,
section ,
sector ,
segment ,
semicircle ,
sextant ,
share ,
subdivision ,
subgroup ,
subspecies ,
theodolite ,
transit ,
transit circle ,
transit instrument ,
transit theodolite
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