DECAGON • FREE TRANSLATOR.ORG • Definition of Decagon

... illustrated by the representation of objects either natural or artificial of the same shape; thus a triangle illustrated by one side of a pyramid, a square, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon. No. 9 monitor has another set of geometrical definitions on the same principle, as a perpendicular line, a horizontal line, an oblique line, parallel lines, curved lines, diverging or converging lines, an obtuse angle, a circle. No. 10 a different ...

— The Infant System - For Developing the Intellectual and Moral Powers of all Children, - from One to Seven years of Age • Samuel Wilderspin