**
Asymptote
** -
A line that a graph approaches without touching.

**
Axis of Symmetry
** -
The line over which a graph can be reflected without altering the graph.

**
Hole
** -
A single point at which a function has no value.

**
Horizontal Asymptote
** -
If a graph has a horizontal asymptote of *y* = *k*, then part of the graph
approaches the line *y* = *k* without touching it -- *y* is almost equal to *k*,
but *y* is never exactly equal to *k*.

**
Symmetry
** -
If a graph does not change when reflected over a line or rotated around a point,
the graph is symmetric with respect to that line or point.

**
Vertical Asymptote
** -
If a graph has a vertical asymptote of *x* = *h*, then part of the graph
approaches the line *x* = *h* without touching it -- *x* is almost equal to *h*,
but *x* is never exactly equal to *h*.