Microsoft Office

In Word, a style defines a set of formatting properties that are indirectly applied to characters, paragraphs, list, or tables. Instead of directly applying bold, then 14 point font, and then red to text, you can use a style to indirectly apply these three things in a single click. This is useful because you can quickly and consistently apply rich formatting, and can later change the definition of the style all the text the style is applied will change.

For example, the Heading 1 style in Word 2003 specifies the font, font size, and font color properties (among others) as: Arial, 16 point, and automatic, while in Word 2007 Heading 1’s font, font size, and font color properties are: Cambria, 14 point, and blue-Accent 1-Darker 25%. Because these properties changed Between Word 2003 to Word 2007, applying the Heading 1 style in Word 2003 will give you a different looking heading than if you did the same thing in Word 2007. And if you are not a big fan of Heading 1 in 2003 or 2007, you can change the font, font size, and font color properties in both versions and those changes will be applied to every instance of Heading 1 in the given document. Quick, consistent, and rich formatting that can be changed once and trickle through the whole document.

How styles relate to one another

You may be wondering how Word deals with all this style. I can get you 80% of the way there with a relatively simple explanation. The remaining 20% is more complex and less common, so I’ll go there only if I need to in later posts.

In short, styles build on top of one another. For example, if you have a numbered paragraph in a table, then the style layering logic in Word essentially works like this [Word is "speaking" in the example]:

“Document Defaults, tell me what properties to apply to paragraphs and characters by default.”
“Table Style, tell me how the table should look—i.e., row shading, borders, etc.—and if you have any additional paragraph and character properties (i.e., stuff not in the Document Defaults). If you have additional properties, I’ll add them. If you have any of the same properties as the Document Defaults—such as line spacing—but different values for those properties—such as 1 vs. 1.5—I’ll use yours.”
“Paragraph Style, do you have any additional paragraph properties (i.e. stuff not in the Document Defaults or Table Style) that I need to apply to this paragraph? If you specify the same paragraph properties as the any of the previously applied styles I’ll use yours.”
“Numbering Style, tell me how the numbered list should look and if you’ve got additional paragraph properties that I don’t have yet. Of course, if you have different values for properties that I do already have, I’ll use yours.”
“Character Style, do you have any additional character properties (i.e. stuff not in the Document Defaults or Table Style) that I need to apply? If you have the same character properties as the any of the previously applied styles, I’ll use yours.”
“Is there any direct formatting—bold, italics, underline, font color, etc.—applied? If so, I’ll use those.”
This story hopefully illustrates that:

Multiple styles can be applied to the same part of a document, so properties defined in styles are applied in a specific order.
The properties set by one type of style can be supplemented or superseded by other types of styles.
The general hierarchy of style types is [from lowest to highest priority]:
Document Defaults
Table Styles
Paragraph Styles | Paragraph Part of Linked Styles
Numbering Styles
Character Style | Character Part of Linked Styles
Direct Formatting