Sabbatical is often still associated with universities where students or professors take time off from their regular duties to pursue some other activity in a remote region. This is typically, but not always, associated with their normal duties, such as a biologist that lives in the rain forest for a year to conduct research. This made more sense in the past, when travel was long and expensive.
It can mean just an extended break from work, but the connotation to most is that the break is used to engage in another project that your day job constrains in some way. It also implies that you will return to your previous duties afterwards.
The trend is to call a temporary leave of absence from your job to do whatever a "career break."