Really the two things are very similar. But we do get asked about the differences between these two terms.
Both are terms that refer to adapting your design to fit the specific constraints of a mobile device / mobile browser. They come from different people and you can read about what the different people thing here (Aaron Gustafson – father of adaptive design), here (Ethan Marcotte, who coined the term responsive design), and a nicely nuanced piece here on Quora and a much weaker response posted on LinkedIn Answers. [Note to self: don’t forget about Quora when looking for sites to attract prospects to my clients’ websites!]
In any event, the hallmarks of responsive design include:
- fluid grids
- fluid images / media
- media queries
These are (quite) nerdy things but to make a long story very short, media queries are used to figure out what kind of device and browser you are using and serve up content in that is optimized by device size and also by browser.
One thing I didn’t realize until quite recently is that with responsive design and media queries, your fonts will look different on the desktop web. This is because of the different rendering engine inside of Chrome vs. Firefox.