ARLES JOHN HUFFAM DIKKA
DICKINSON, ANNA ELIZABETH DILAPIDATION
DICKINSON, JOHN DILATATION
DICKSON, SIR ALEXANDER DILATORY
DICKSON, SIR JAMES ROBERT DILEMMA
DICOTYLEDONS DILETTANTE
DICTATOR DILIGENCE
DICTIONARY DILKE, SIR CHARLES WENTWORTH
DICTYOGENS DILL
DICTYS CRETENSIS DILLEN, JOHANN JAKOB
DICUIL DILLENBURG
DIDACHE, THE DILLENS, JULIEN
DIDACTIC POETRY DILLINGEN
DIDEROT, DENIS DILLMANN, CHRISTIAN AUGUST
DIDIUS SALVIUS JULIANUS, MARCUS DILLON, ARTHUR RICHARD
DIDO DILLON, JOHN
DIDON, HENRI DILUVIUM
DIDOT DIME
DIDRON, ADOLPHE NAPOLEON DIMENSION
DIDYMI DIMITY
DIDYMIUM DINAJPUR
DIDYMUS DINAN
DIDYMUS CHALCENTERUS DINANT
DIE (town of France) DINAPUR
DIE (datum) DINARCHUS
DIEBITSCH, HANS KARL FRIEDRICH ANTON

DIAMETER (from the Gr. [Greek: dia], through, [Greek: metron],
measure), in geometry, a line passing through the centre of a circle or
conic section and terminated by the curve; the "principal diameters" of
the ellipse and hyperbola coincide with the "axes" and are at right
angles; "conjugate diameters" are such that each bisects chords parallel
to the other. The diameter of a quadric surface is a line at the
extremities of which the tangent planes are parallel. Newton defined the
diameter of a curve of any order as the locus of the centres of the mean
distances of the points of intersection of a system of parallel chords
with the curve; this locus may be shown to be a straight line. The word
is also used as a unit of linear measurement of the magnifying power of
a lens or microscope.

In architecture, the term is used to express the measure of the lower
part of the shaft of a column. It is employed by Vitruvius (iii. 2) to
determine the height of a column, which should vary from eight to ten
diameters according to the intercolumniation: and it is generally the
custom to fix the lower diameter of the shaft by the height required and
th