Dear hev: I'm ignorant of math, but look at defintions 3 and 4"
intercept
vt.
5< L interceptus, pp. of intercipere, to take between, interrupt < inter3, between + capere, to take: see HAVE6
1 to seize or stop on the way, before arrival at the intended place; stop or interrupt the course of; cut off !to intercept a forward pass"
2 [Now Rare] a) to stop, hinder, or prevent b) to cut off communication with, sight of, etc.
3 Math. to cut off, mark off, or bound between two points, lines, or planes
n.
1 Math. the part of a line, plane, etc. intercepted
2 Mil. the act of intercepting an enemy force, esp. enemy aircraft
in#ter[cep4tion
n.
in#ter[cep4tive
adj.