The straight line according to Ozanam ---------------------
In 1691, Jacques Ozanam (1640–1717) published his Dictionnaire mathématique ou idée générale des mathématiques (Mathematical Dictionary, or a General Idea of Mathematics). In it, he catalogued the mathematical terms in use at the time, and the definitions strike us today as thoroughly naïve. The straight line held pride of place, at the very start of the chapter on "speculative geometry".
"The line is an extension in length, without breadth or depth. It is evident that the extremities of a line are points: since it begins with a point, it must end with a point. It can be Straight & Curved.
The Straight Line is that which has all its parts evenly disposed between its extremities, such that one of its parts rises & falls no more than the other. It is evident that the Straight Line is unique, that is to say that there are not several kinds of straight lines.