numerical analysis: (mathematics) the branch of mathematics that studies algorithms for approximating solutions to problems in the infinitesimal calculus
pure mathematics: the branches of mathematics that study and develop the principles of mathematics for their own sake rather than for their immediate usefulness
static line: a cord used instead of a ripcord to open a parachute; the cord is attached at one end to the aircraft and temporarily attached to the pack of a parachute at the other; it opens the parachute after the jumper is clear of the plane