A line that a graph approaches but never touches is called an:

1. Some graphs get closer and closer to a line without meeting it. 2. That line has a name of its own. 3. Whenever a graph approaches a line but never touches it, that line is an asymptote. 4. So the answer is an asymptote. _Source: OpenStax Intermediate Algebra 2e (CC BY 4.0), Ch 10, sections 10.1-10.2 'Evaluate and Graph Exponential Functions'_