A line that intersects a circle in exactly one point.
End behavior is a description of the trend of a function as input values become very large or very small, represented as the 'ends' of a graphed function.
A horizontal asymptote is a horizontal line that indicates where a function flattens out as the independent variable gets very large or very small. A function may touch or pass through a horizontal asymptote.
A limit is the value that the output of a function approaches as the input of the function approaches a given value.
Limit notation is a way of expressing the fact that a function gets arbitrarily close to a value.
A secant line is a line that joins two points on a curve.
A tangent line is a line that "just touches" a curve at a single point and no others.
Introduction to the concept of limit and the origins of calculus.