This is a neat interactive page by Ville V. Vanninen to reference the names of things in the CSS syntax. I feel like the easy ones to remember are “selector,” “property,” and “value,” but even as a person who writes about CSS a lot, I forget some of the others. Like the property and value together (with the colon) is called a declaration. And all the declarations together, including the curly brackets (but not the selector)? That’s a declaration block, which is slightly more specific than a block, because a block might be inside an at-rule and thus contain other complete rule-sets.