Conjugate, from L. conjungo, to yoke or join together; from L. con, together;

and L. jugum, that which joins, a yoke.

Converge, from F. converger, L. con

with; L. vergo, to bend, or incline.

Co-ordinate, from L. co (con), together; and L. ordo, inis, a straight row, a regular series.

Cube, from L. cubus; G. kubos, a die.

Curve, from L. curvus, a, um, crooked, bent.

Cylinder, from G. kylindros; from G. kylindō, to roll. Hence roller-like.

Decagon, from G. deka, ten; and G. gōnia, an angle (corner).

Decimal, from L. decem, ten.

Diagonal, from G. diagōnios, from corner to corner. [G. dia, through; and G. gōnia, a corner.]

Diagram, from G. diagramma, that which is marked out by lines; from G. dia, round; and G. graphō, to write or delineate.

Diameter, from G. diametros, measurement through; from G. dia, through; and G. metron, a measure.

Dihedral, from G. di, double; and G. hedra, a base.

Dodecagon, from G. dōdeka, twelve; and G. gōnia, an angle (corner).
Dodecahedron, from G. dōdeka, twelve; and G. hedra, a base.

=

Duodecimal, from L. duodecim, twelve. [L. duo two, and L. decem = ten.]

Elevation, from L. elevo, to lift up or raise; from L. e, up; and L. levo, to raise.

Ellipse, from G. elleipsis, a defect or leaving out. [G. elleipo, to leave out.] Equilateral, from L. aequilaterus, equal-sided; from L. aequus, a, um, equal; and L. latus, lateris, a side.

Equivalent, from L. aequus, a, um, equal; and L. valens, valentis, being strong. [L. valeo = to be strong.]

Focus, from L. focus, a fire-place, hearth. [L. foveo
Foil, from F. feuille, a leaf. [L. folium = a leaf.]

Geometry, from G. yeōmetrō, to measure land; from G. gē, the earth; and G. metro, to measure.

Heptagon, from G. heptagōnos, seven-cornered; from G. hepta, seven; and G. gōnia, an angle (corner).

Hexagon, from G. hex, six; and G. gōnia, an angle.

Horizontal, from G. horizō, to divide or bound. [G. horos a limit.]

Hyperbola, from G. hyperbolē, a throwing beyond; from G. hyper, beyond or over; and ballo, to throw.

Hypotenuse, from G. hypoteinousa, the line subtending a right angle; from G. hypo, under; and G. teinō, to stretch.

Icosahedron, from G. eikosi, twenty; and G. hedra, a base.

Intersect, from L. inter, between; and L. seco (sectum), to eut.

Involute, from L. involvo, to roll around, wrap up; from L. in, upon; and L. volvo, volutum, to roll.

Isosceles, from G. isoskelēs, having equal legs; from G. isos, equal; and G. skelos, a leg.

Line, from L. linea, a linen thread. [L. linum

flax.]

Multilateral, from L. multilaterus, many-sided; from L. multus, a, um, many; and L. latus, lateris, a side.

Nonagon, from L. nonus, a, um, the ninth; and G. gōnia, a corner.

Oblique, from L. obliquus, a, um, sidelong, slanting.

Oblong, from L. oblongus, a, um, rather long.

Obtuse, from L. obtusus, a, um, blunt; from L. obtundo, to blunt; from

L. ob, against; and L. tundo, to beat.

Octagon, from G. oktō, eight; and G. gōnia, an angle.

Octahedron, from G. oktō, eight; and G. hedra, a base.

Ordinate, from L. ordo, inis, a straight row, a regular series.

Parabola, from G. parabolē, a placing beside; from G. para, from, by the side of; and G. ballo, to throw.

Parallel, from G. para, by the side of; and G. allelos, one another. [G. allos = another.]

Parallelogram, from G. parallēlogrammon, a figure bounded with parallel sides. [G. grammē = a line.]

Penetration, from L. penetro (penetratum), to place or set into.

Pentagon, from G. pente, five; and G. gōnia, a corner.

Perimeter, from G. peri, around; and G. metron, a measure.

Periphery, from G. peri, around; and G. pherō, to carry.

Perpendicular, from L. perpendiculum, a plumb - line; from L. per, thoroughly; and L. pendo, to weigh.

Plane, from L. planus, perfectly flat.

Point, from L. punctum, a point, or small hole. [L. pungo to pierce into ]

Polygon, from G. polugōnos, a figure having many angles; from G. polus, many; and G. gōnia, a corner.

Problem, from G. problēma, that which is proposed; from G. pro, before; and G. ballo, to throw.

Profile, from L. pro, forth; and L. filum, a thread.

Projection, from L. projicio (projectum), to throw forth or before; from L. pro, forth; and L. jaceo, to throw.

Proportional, from L. proportio, symmetry, analogy; from L. pro, in comparison with; and L. portio, portionis, part, share.

Pyramid, from G. pyramis, pyramidos, usually derived from G. pyr, a flame, because of its pointed shape.

Quadrant, from L. quadrans, -antis, making square; from L. quadro, to make square. [L. quatuor = four.]

Quadrilateral, from L. quadrilaterus, four-sided; from L. quatuor, four; and L. latus, lateris, a side.

Quatrefoil, from F. quatre, four; and F. feuille, a leaf.

Radius, from L. radius, a spoke of a wheel.

Ratio, from L. ratio, calculation. [L. reor (ratus), to think, suppose.]
Rectangle, from L. rectus, a, um, right; and L. angulus, a corner.

Rectilineal, from L. rectus, um, right, straight; and L. linea, a linen thread. [L. linum =

flax.]

Rhombus, from G. rhombos, a wheel thus shaped, and turned on a pivot. [G. rhembo, to turn round and round.].

Rhomboid, from G. rhombos, and G. eidos, form, shape.

Scale, from L. scala, a ladder, flight of steps. [L. scando, to mount.]
Scalene, from G. skalēnos, unequal, uneven.

Sector, from L. sector, one who cuts. [L. seco

[G. skazō, to limp.]
(sectum), to cut.]

Segment, from L. segmentum, a piece cut off. [L. seco (sectum), to cut.] Semi-circle, from L. semi, half; and L. circulus, a ring; from G. kirkos, a circle.

Sphere, from G. sphaira, a ball or globe.

Spiral, from G. speira, anything wound round, a coil.

Square, from L. quadro, to make square. [Old F. esquarré, a square; modern F. carré, square.]

Superficies, from L. superficies, the upper side, the top; from L. super, above; and L. facies, a face.

Tangent, from L. tangens, -entis, touching. [L. tango
Tetrahedron, from G. tetra, four; and G. hedra, a base.
Trace, from L. traho, to draw. [F. trace

trace.]

=

to touch.]

Transverse, from L. transversus, lying across; from L. trans, across; and L. verto (versum), to turn.

Trapezium, from G. trapezion, dim. of trapeza, a table; contracted either from G. tri-peza, three-legged; or from G. tetra-peza, four-legged. Trapezoid, from G. trapezion, and G. eidos, shape, form.

Trefoil, from F. trois, three; and F. feuille, a leaf.

Triangle, from L. triangulus, having three corners; from L. tres, three; and L. angulus, a corner.

Trilateral, from L. trilaterus, having three sides; from L. tres, three; and L. latus, lateris, a side.

Trisect, from L. tres, three; and L. seco (sectum), to cut.

Vertex, from L. vertex, the top or crown of the head. [L. verto = to turn.] Vertical, from L. vertex (verticis), the top of the head.

Volute, from L. volvo (volutum), to roll.

INDEX TO PROBLEMS IN PLANE GEOMETRY.

PAGE

25

10

11

11

13

...

...

14

14

10

6

54

55

170

45

45

46

48

49

98

98

99

...

; to make, equal to given angle, from given point, in the given
line,

; to make, equal to given angle, from given point, outside the
given line,

; to bisect, made by two converging lines, the angular point
being inaccessible,

tangential; to draw, to two given circles, touching one of the
given circles in a given point,

of a circle; to describe, tangential to two given converging
lines,

; to describe, tangential to given arc and given line,

Circle;

to find centre of,

...

...

; to describe, passing through three given points,

...

...

; to describe, passing through given point, and tangential to
given line,

; to describe, of given radius, touching two given circles,

; to describe, of given radius, tangential to two converging lines,
; to draw, touching given circle in given point, also a given line,