Bullet Journal: A definition
Updated: Nov 6, 2020
In some ways it is better the think of bullet journalling as a method, or a practice. When people talk about bullet journals as an object they just mean the notebook that they are using to bullet journal in.
The bullet journal method is a method of drawing up a form of organisational journal in a notebook as you go, following the system described by Ryder Carol. Ryder used the term 'bullet journaling' to describe a journaling method he had been developing. The method has it's more core features, but it is constantly being expanded as people find ways to customise it. The features of the original method are not even hard-and-fast; they are more like foundational techniques that you may retain or shape slightly as you cusotmise your own method.
Ryder Carrol describes the method here: https://bulletjournal.com/
The bullet journal method recommends a form of short-hand, using symbols the categorise information, as well as promoting intentional notes. The symbols are called bullets, and this is how the method got its name. However, the bullet journal method is actually much broader system than this one technique: it has techniques for organising large and small time frames, managing projects, and organising fairly scattered topics neatly in one place. However, you could forego much of this while still practicing the method. One form of this would be to take the simplest aspects of the bullet journalling and keep your journalling style more free-form.
From observing the system and trying out a few different forms of it myself, I firmly believe there is a blurred line around what constitutes bullet journalling. As fore-mentioned, the bullet journal system was first articulated by one person. Acknowledging that, I suggest thinking of it like this: if the journaling method one is using seems to have a fair bit of that bullet journal DNA in it, then it could reasonably be called bullet journalling.
What bullet journaling is not is a hard system defined by a page-spread you might see from any one person e.g. someone from social media.
What bullet journaling is is a deeply customisable and adpative system based on some core techniques. These techniques are kind of like the common ancestor of the many page spreads you might come across. If you would like to get to know these techniques, I suggest starting out on the website, https://bulletjournal.com/ , and then expanding to various resources including blogs such as this one to gather ideas for you own customisations. Over time you will have not only have a solid idea of what bullet journalling is and how to practice it - you will gain an idea of the variation which is yours.