ABSTRACT
This chapter presents a list of terms covering the concepts of mathematics. The terms include Diameter, The number ten: decimal system, The sun's rays and length of shadows, and appearance of the half-moon. Both Aristotle and Euclid regularly use the word diameter for the diagonal of a parallelogram as well as for the diameter of a circle. Euclid defines only the diameter of a circle: A diameter of a circle is any straight line drawn through the centre and terminated in both directions by the circumference of the circle, and such a straight line also bisects the circle. The circle 'made or defined by the sun' as it illuminates the moon is called by Aristarchus of Samos 'the great circle which divides the dark and the light portions of the moon', On the Sizes and Distances of Sun and Moon, and this circle, as he says, 'is in the direction of the eye when the moon appears to us halved'.
