Notebook documents (or “notebooks”, all lower case) are documents produced by the Jupyter Notebook App, which contain both computer code (e.g. python) and rich text elements (paragraph, equations, figures, links, etc…). Notebook documents are both human-readable documents containing the analysis description and the results (figures, tables, etc..) as well as executable documents which can be run to perform data analysis.
In fact, notebooks (being a standardised format) are now supported by a bunch of applications other than the Jupyter Notebook App, and some of these support languages other than Python (e.g. R).
Google Colab supports Python notebooks. Here's one I developed to explore Jesse Livermore's Dec 2013 essay "The Single Greatest Predictor of Future Stock Market Returns": <https://colab.research.google.com/drive/1PkE07zbuCKykMcfBOzxlCwv2u5EumkX1?usp=sharing>
A Google sign-in is required to interact with the code, otherwise you just see a static view based on the last time I executed it.
I like that these notebooks can be easily published and support collaboration. Has anyone else had a chance to play?