Question: I've noticed that some popular naming conventions have been given names to make it easier to communicate about them. Two examples are Pascal Case and Camel Case.

I would like to know if there is a common name for a convention I have seen used in CSS. In this naming convention, all letters are lower-case and words are separated by hyphens. I don't know if this convention is CSS-specific.

Examples of names with this convention:

* red-car
* ticket
* xml-code

Answer: 
I've seen the term 'spinal-case' used in the AngularJS documentation to describe this naming convention.

Having done no further investigation I can't confirm if this name has been widely adopted though...
I think there is no (commonly used) special term for this naming convention.
So, just use a self-describing name for it, like:

* lower-case with dashes / hyphens
* hyphenated lower-case
* hyphen-separated-lowercase-words