Q:

What is a Sass % (percent) selector called?

Im trying to understand the naming of the % sign in Sass, and im not sure what to call it when I use it.
I know that when using "$" its called a variable and can only really store one rule like for example:
$variable: #FFFFFF;

But sometimes I use "%" for extends in my Sass like this:
%style {
    color: #FFFFFF;
    padding: 20px;
}

what is my "%style" called? is it a Sass object? or module or? Can someone shine some light on this. I cant seem to find the information when Googling.

A:

Selectors that contain % are referred to as "placeholder selectors".
From the Sass Documentation:

Sass has a special kind of selector known as a “placeholder”. It looks and acts a lot like a class selector, but it starts with a % and it's not included in the CSS output. In fact, any complex selector (the ones between the commas) that even contains a placeholder selector isn't included in the CSS, nor is any style rule whose selectors all contain placeholders

