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Eng ID Term Definition
4941
sphere
A curved surface all points of which are equi­distant from a fixed point within, called the centre.
4942
spherical aberration
See ABERRATION OF LIGHT.
4943
spherical buoy
See BUOY.
4944
spherical coordinates
See COORDINATES.
4945
spherical excess
The amount by which the sum of the three angles of a spherical triangle exceeds 180°.
4946
spherical sailing
See SAILING.
4947
spherical wave
See WAVE.
4948
spheroid
An ellipsoid; a figure resembling a sphere. Also called ellipsoid or ELLIPSOID OF REVOLUTION, from the fact that it can be formed by revolvi... more
An ellipsoid; a figure resembling a sphere. Also called ellipsoid or ELLIPSOID OF REVOLUTION, from the fact that it can be formed by revolving an ellipse about one of its axes. In GEODESY, this term is fre­quent­ly used to mean REFERENCE SPHEROID. See also SPHEROID: OBLATE and SPHEROID: PROLATE.
4949
spheroid: oblate
An ELLIP­SOID OF REVOLUTION, the minor AXIS of which is the AXIS of REVOLUTION. The EARTH is approximately an oblate spheroid.
4950
spheroid: prolate
An ELLIPSOID OF REVOLUTION, the major AXIS of which is the AXIS of REVOLUTION.
4951
spheroid of reference
See REFERENCE SPHEROID.
4952
spicule
A minute needlelike or multiradiate calcare­ous or siliceous body in sponges, radiolarians, primitive chitons, and echinoderms. They frequen... more
A minute needlelike or multiradiate calcare­ous or siliceous body in sponges, radiolarians, primitive chitons, and echinoderms. They frequently are identi­fied in marine sediment samples.
4953
spilling breaker
See BREAKER.
4954
spindle
A spar serving as a BEACON. A slender pin or rod, as one constituting part of a machine.
4955
spire
A pointed structure extending above a building. The spire is seldom less than two‑thirds of the entire height and its lines are rarely broke... more
A pointed structure extending above a building. The spire is seldom less than two‑thirds of the entire height and its lines are rarely broken by stages or other features. The term is not applied to short pyra­mid-shaped structures rising from a tower or belfry.
4956
spirit bubble
See LEVEL: SPIRIT.
4957
spirit compass
See COMPASS: LIQUID.
4958
spirit level
See LEVEL.
4959
spirit level axis
See AXIS OF SPIRIT LEVEL.
4960
spirit levelling
See LEVELLING.