A line that touches a circle at exactly one point and which makes a right angle with the circle's radius. For example, a circle that fills a square has four tangent points and the square's sides are tangent lines. An arc (curve) in a survey is part of a larger circle. One can construct tangent lines at the end points of the arc.

a line that is tangent to the graph of a specified function of one argument at a specified value of its argument

a line, which touches a given curve at a single point

a line which touches the circle at one point but does not intersect it

a straight line that touches our circle only at a single point

The imaginary line drawn perpendicular to the impact line of the cueball and object ball. The cueball will travel along this line if no vertical spin is applied (ie. it is sliding). One of the most critical concepts in understanding Pool.

one of the critical concepts in pool. The tangent line is an imaginary like that is perpendicular to the line the object ball will follow on any shot that is not straight in. If the cue ball strikes the object ball while it is still skidding, i.e. with out any forward or backward roll, it will move along the tangent line after striking the object ball. This single concept is the basis for all position play in pool. The use of follow and draw allows you to modify the path of the cue ball in relation to the tangent line. Follow will cause the cue ball to travel forward of the tangent line, while draw forces the cue ball to travel a path behind the tangent line.