DECLARATION BLOCK Contains one or more declarations separated by semicolons. Each individual declaration includes a property within the CSS, including its name and value, which is separated by a colon. Used to keep separate CSS code from overlapping into dedicated blocks of code with specific purposes.

1. CSS VOCABULARY GLOSSARY
ADJACENT SIBLING COMBINATOR
Selects only the specified adjacent element that immediately follows the
former element.
AT-RULE
An instruction to the CSS parser. Begins with @, followed by identifier.
ATTRIBUTE SELECTOR
Selects elements with a specific attribute that is relevant to a class selector, but
requires a specific term you are focusing on.
BLOCK
Display option that includes an entire section of CSS, separated by other blocks of
codes with separate rules, properties and purposes.
CHILD COMBINATOR
The selector matches all elements that are the immediate children of a
specified element.
CLASS SELECTOR
Uses a class attribute to select a specific element with ".", rather than an ID using
"#". A class selector is more universal when applying code to a section of a CSS
document, whereas an ID only focuses on one section of the content.
COLOR
Sets color of element, allows any CSS color to be applied to properties, fonts and
even page backgrounds.
COMBINATOR
Explains the relationship between selectors.
COMMENT
Ignored by browsers and offset by /* and */. Useful to explain code to users
or share insight about specific portions of the code and what each individual
section means.
DECLARATION
A property name and a value separated by a colon. Generally begins a new section
within the CSS document.
DECLARATION BLOCK
Contains one or more declarations separated by semicolons. Each individual
declaration includes a property within the CSS, including its name and value, which
is separated by a colon. Used to keep separate CSS code from overlapping into
dedicated blocks of code with specific purposes.
DESCENDANT COMBINATOR
Combines two selectors in such a way that the elements matched by the second
selector are selected if they have an ancestor element matching the first selector.
EXPRESSION
An expression is useful to avoid setting CSS to a constant, and instead including
other programs such as Java within the CSS code.
FUNCTION
Functions are not always found in CSS documents. Integrating CSS into
programming may require a function important to the document, allowing the CSS
to show properly within an application or on a website.
GENERAL SIBLING COMBINATOR
Separates two selectors and matches the second element only if it is preceded by
the first and both share a common parent.
ID SELECTOR
Uses the ID attribute of an HTML element to select a specific element. Specifying a
name of the property you want to target requires the "#" attribute before naming
the element.
KEYWORD
A word defined within the CSS specs, never in quotes.
LENGTH
A measurement with a numeric value and a unit, indicating the length of a
given area. Mostly used when editing sections of web pages and defining total
size allotted.
MEDIA FEATURE
A way to use media queries to target styles depending on the feature of
that medium (i.e., min-width and max-width). It is also useful for responsive
design integration.
MEDIA QUERY
Uses @media rule to include a block of CSS only if a certain condition is true.
CSS3 introduced a module to help with improving more web responsive pages
that include CSS, which is now revolutionary with many individuals browsing
online using mobile phones.
MEDIA QUERY LIST
A comma-separated list of media queries, usually informing users or other
developers of specific media queries in place.
MEDIA TYPE
Where style sheets will be presented (on screen, on paper, with a speech
synthesizer, etc.).
NUMBER
Either integer or real number, specified in decimal notation, and can have an initial
– or + in front of it. Helps reduce size or format a web page derived from "0".
PERCENTAGE
An integer or a decimal number followed by a percentage character, indicating
some fractional amount. Often useful when defining text and DIV tags, not by
points or pixels but by percentages.
PROPERTY
Defines how styles should look on the web page or elsewhere. Similar to tags in
HTML. There can be hundreds, if not thousands of properties embedded in a CSS
document — giving properties a variety of options in terms of output style and
appearance.
PSEUDO-CLASS
Defines a special state of an element, such as adding unique features to an
element based on the user’s interaction with the element while browsing.
Example: If a user hovers a link and it turns bright orange, a pseudo-class is in
place for that element in the CSS file.
PSEUDO-ELEMENT
Styles specified parts of an element and not an entire class. Highly useful for those
interested in highly customizable CSS files.
RULE-SET
A selector and a declaration block. Rule-sets give users the ability to implement
universal CSS rules within specific declaration boxes of code, saving time and
repetitiveness within the CSS file.
SELECTOR
Used to identify HTML elements based on their element name, ID, class, attribute,
etc. Implemented to highlight the property that is being created or altered.
SIMPLE SELECTOR
Either a type selector or a universal selector, followed immediately by zero or
attribute selectors, ID, selectors or pseudo-classes in any order. A simple selector
is effective for a less complicated CSS file without additional IDs, classes or
attributes required.
STATEMENT
A building block of code that begins with any non-space characters and ends with
the first closing brace or semicolon, helping to identify the selector and property
that is being modified.
STRING
Enclosed in single or double quotes.
TYPE SELECTOR
Type selectors are simple and can be implemented with the same
document language to create new sections and properties. Matches the name
of a document language element type and every instance of the element type in
the document tree.
UNIT
Measurement tool for CSS coders. The most common measuring units
include "px", "pt", a percentage, "vh", and "vw" when aligning and sizing
elements of a page.
UNIVERSAL SELECTOR
Matches the name of any element type and any single element in the
document tree that does not provide additional IDs to focus on.
URL
Used to address a document or other data on the web.
Commonly known as a Uniform Resource Locator.
VALUE
The value of an element provides customization to specific
properties in CSS. Whether changing height, font size or display, values
help to further customize CSS.
VENDOR PREFIX
Code added to support new CSS features, before those features are fully
supported in all browsers. Also utilized to showcase which browsers have
been tested and fit the standards of the CSS code presented.