Jupyter is an offshoot of the IPython project, which aims to create a better interactive mode for Python. While Jupyter incorporates IPython, it's still available as a standalone program.

Jupyter Notebook lets you author visualizations, but also share them and allow interactive changes to the shared code and data set. Code sharing.

I’ve been talking about traditional notebooks, but the next generation interface rolled out last year. Known as JupyterLab, it allows you to use other tools like editors in a tabbed-interface.