The curve traced out by points P and P &nbstress; which lie on lines through a fixed point A where the midpoint M of PP &nbstress; is on a fixed line and the absolute value | PM | = the absolute value | P &nbstress; M | = the absolute value | MO |, where O is the projection of A onto that fixed line.
Origin of strophoidGreek strophos twisted cord ( from strephein to turn ; see streb(h)- in Indo-European roots.) -oid
The equation for this strophoid is
x2(a + x)/(a − x).
- (geometry) A certain kind of curve.