I wonder which form(s) are correct amongst the following:

* We denote scalars with lowercase.
* We denote scalars with lowercase**s**.

[Example](http://www.books.aisc.ucla.edu/AICRJStyleSheet.pdf) (let's ignore the space between *lower* and *cases*):

[![UCLA definition of lowercases](https://i.stack.imgur.com/NYh8y.png)](https://i.stack.imgur.com/NYh8y.png)

[*Lowercase*](https://www.google.com/search?q=lowercase) can be a noun:

[![Google definition of lowercase](https://i.stack.imgur.com/gyrZh.png)](https://i.stack.imgur.com/gyrZh.png)