en.wikipedia.org/wiki/Asymptote

In analytic geometry, an **asymptote** of a curve is a line such that the distance
between the curve and the line approaches zero as one or both of the x or y ...

www.mathsisfun.com/algebra/asymptote.html

An **asymptote** is a line that a curve approaches, as it heads towards infinity: ...
approach from any side (such as from above or below for a horizontal **asymptote**)
,.

mathworld.wolfram.com/Asymptote.html

An **asymptote** is a line or curve that approaches a given curve arbitrarily closely,
... Wolfram Web Resource. http://mathworld.wolfram.com/**Asymptote**.html ...

www.khanacademy.org/questions/what-are-asymptotes/kafb_4768525

An **asymptote** is a line that the curve never touches but approaches. like say the
curve y=1/x will never touch the line x=0(y-axis) nor the y=0(x-axis). so the ...

www.freemathhelp.com/finding-horizontal-asymptotes.html

A horizontal **asymptote** is a y-value on a graph which a function approaches but
does not actually reach. Here is a simple graphical example where the graphed ...

www.freemathhelp.com/asymptotes.html

**Asymptotes**. An **asymptote** is, essentially, a line that a graph approaches, but
does not intersect. For example, in the following graph of y=1x, the line
approaches ...

www.purplemath.com/modules/asymtote4.htm

Purplemath. So far, we've dealt with each type of **asymptote** separately, kind of
like your textbook probably does, giving one section in the chapter to each type.

www.purplemath.com/modules/asymtote2.htm

Uses worked examples to explain how to find horizontal **asymptotes**. Explains
how functions and their graphs get "close" to horizontal **asymptotes**, and shows ...