DICTIONARY


Ten means explained original: "medietates". This refers to the various types of mathematical means, such as arithmetic, geometric, and harmonic.	366	Diameter of a section	291, 293, etc.
Two second definitions	334	Assumed diameters of conic sections	335
Thirteen third definitions	336	Conjugate diameters	314
4 definitions of Commandino Federico Commandino was a 16th century mathematician known for translating Greek works into Latin.	400	Conjugate diameters	335
Five definitions	18	Diameters of the three sections, which ones	288
Five conic definitions	35	Similar portions of diameters	360
6 specular definitions Refers to the geometry of mirrors and reflections.	504	Multiplying transparent media Usually refers to lenses or substances that refract light multiple times.	519
Seven definitions of Archimedes	93	Transparent and opaque	477
Seven definitions of Valerio Luca Valerio was an Italian mathematician who worked on centers of gravity.	406	Longitude of Dieppe	270
10 optical definitions	477	The 24-hour day, where it occurs	248
Seven definitions	12	The longest day of any climate	269
14 dioptric definitions Dioptrics is the study of the refraction of light through lenses.	514	Dinet's excellent treatise on God, preface point 14 Pierre Dinet was a contemporary author whose philosophical works Mersenne often referenced.
14 catoptric definitions Catoptrics is the study of the reflection of light by mirrors.	500	Dioptrics	472
15 definitions of Serenus Serenus of Antinoöpolis was a Greek mathematician who wrote on the sections of cylinders and cones.	314	Explanation of dioptric instruments	518
Sixteen perspective definitions	543	Definition of the line of direction: motion	433
18 definitions of parallaxes	530	How great the distance of perfect vision is	546
19 definitions of Mydorge Claude Mydorge was a French mathematician and friend of Descartes.	332 and 333	How distance is known	493
19 definitions of Apollonius, 278, and then others	282	Division of a ratio	14
23 definitions of Euclid, 21		Dodecahedron and its diagonal	89 and 42
Thirty-five definitions of Euclid	1	Measurements of barrels original: "Doliorum". This refers to the geometric calculation of volumes for wine casks.	176
Demetrius	368	Dositheus	92
Right and left appear reversed Refers to the lateral inversion of images in a mirror.	505	Dositheus 92, 104, 124, and 130 Dositheus of Pelusium was a Greek mathematician to whom Archimedes addressed several works.
Diagonal	73	Two mean proportionals	101
Diagonal of a cube	87	Twelve postulates of Archimedes	142
Diagonal of an octahedron	88
Diagonal of an icosahedron	89	E
Diameter	1 and 67
Second diameter	335	Ecliptic, the place of the stars	263
Principal diameter of a conic section	ibid.	Duties of the ecliptic	ibid.
What the transverse diameter is	ibid.	Similar ellipses	314
Visual diameter always remains constant to itself	550	How great the area of an ellipse and parabola is	170
Diameter of the world compared with the diameter of the earth	159	Generation of an ellipse, 281; definition	334
Diameter of a curved line	314	Elliptical mirrors	513
Diameter of a conic section	333	Eratosthenes' mesolabe The mesolabe was a mechanical instrument used to find mean proportionals.	365
What the straight diameter is	278	Euclid's Phenomena A work on spherical astronomy and the geometry of the heavens.	249
Second diameter	282	Eudemus 274 and 276; Pergamus	305
Second diameter	314	Discoveries of Eudoxus	92
Diameter incommensurable to the side	40	What Eudoxus discovered in Geometry	ibid.
Diameter of gravity 397; diametral plane		Eudoxus makes the sun nine times the size of the moon	155
Diameter and radius of a sphere compared to the sides of regular solids	50	Eutocius's reasoning disproved Eutocius of Ascalon was a commentator on Archimedes and Apollonius.	330
		Exoctahedron This likely refers to a hexahedron or cube, or a specific variant used in 17th-century solid geometry.	59 through 63