The excellent data visualisation blog Flowing Data had a good one on The Many Terms For Visualisation. It's a bit focussed on the geeky end of the data visualisation world the author works in, but it's pretty good.
In general in the wild...
data visualisation or visualisation tends to be used when people are talking about something that is first and foremost
a tool for people already interested in a topic to ask their
own questions and find things out, drilling down into the data or facts. Getting casual people interested
in the topic is a secondary aim (if an aim at all). They're usually
complex, often interactive, and have a design that is led by form-follows-function
and signal-to-noise principles.
Infographic tends to be used for information-based graphics that are
the other way around: first and foremost about attracting and
intriguing people with a low level of interest in the topic and
turning disinterested people into keenly interested people. Enabling
keen people to drill down into data and ask their own questions is a
secondary aim, if an aim at all. They are often static images to aid sharing via social media, and usually (when done well) have a
design focused on creating a strong, attention grabbing visual
hierarchy and a clear narrative flow.
In short, data visualisations are things a person comes to and interrogates, and infographics, things people are drawn to and read.
Of course, there's a huge amount of overlap between the two and the best examples of information design achieve both these aims and work as both visualisations and infographics: attracting people, creating interest, and then enabling them to drill down into facts and data they previously didn't think they were interested in.
Part of the reason there's a terminological divide (which is narrowing: as the discipline improves, more people don't see any sharp distinction) is that there is still something of a cultural divide:
- visualisations tend(ed) to be lead by analytical people (statisticians, programmers, researchers, scientists, technically oriented designers)
- infographics tend(ed) to be lead by communications people (marketeers, illustrators, copywriters, journalists, creatively oriented designers)
This cultural divide is thankfully closing, and the best information graphics come from teams with a healthy mix of analytical and communications people.