Dear Gaby,
Well I would Say that Any line that intersects a given circle at two different points is called a SECANT and part of secant intercepted between these points is called CHORD of a circle. So basically, Both are very same. ... A Chord connects two points on the circumference of a circle. I hope I could help you my friend and Keep on Rockin'
Wishing you some Rockin' Answers,
Mangle