I recently saw someone using 'Categorial variables' while talking about Loss functions.

However, I think in English that word is rarely used. The frequency is 10 times less than the proper word "categorical" recently, and more than 200 times less than "categorical" before 1910 AD.

[![enter image description here](https://i.stack.imgur.com/TwO6P.png)](https://i.stack.imgur.com/TwO6P.png)

Is it just originated from a typo?