n. the axioms for Euclidean geometry that assert that:
a straight line may be drawn from any point to any other point;
a finite straight line may be extended continuously in a straight line;
a circle may be described with any center and any radius;
all right angles are equal to one another; and
if a straight line meets two other straight lines so as to make the sum of the two interior angles on one side of the transversal less than two right angles, the other straight lines, extended indefinitely, will meet on that side of the transversal.
Equivalently, the last axiom may be replaced by Playfair's axiom.