What is the style used for visited hyperlink in MS Word?

The color of visited hyperlinks is determined by the font color of the built-in style named “FollowedHyperlink”. To change the color, you need to modify that style. For Word 2007, 2010, and 2013, follow these step-by-step instructions:

1. From the “Home” tab, click the small arrow icon in the lower-right corner of the “Styles” box. Alternately, you can use Alt+Ctrl+Shift+S.
2. Select the “Options…” link in the lower-right corner.
3. In the “Select styles to show:” dropdown menu, select “All styles“. You will now have an option for “FollowedHyperlink” in the “Styles” list.
4. In the “Styles” menu, hover your mouse pointer over “FollowedHyperlink”, and then click the triangle that appears to the right. From the drop-down menu that appears, select “Modify…“.
5. In the “Formatting” section, choose the color you want to use, then click “OK“.

You have successfully changed the color of hyperlinks in your Word document.

It would help if you say what version of Word you have.

While it is true to say that there are two character styles, for Hyperlink and FollowedHyperlink, this is not the whole story. It is made more complicate by the fact that the text in the document only shows that it is using the "Hyperlink" style, the "FollowedHyperlink" only shows up depending on whether the current reader of the document has visited that URL from this link or not (this seems to be the reason for the term "Followed Hyperlink" as distinct from "Visited Hyperlink" which would include URLs you already visited independently of this link)

If you are using Word 2007 or 2010 a better way to control the colour of this is by changing the colours in the theme which relate spefically to Hyperlinks. These are the colours used in turn by the two styles.

Go to Page Layout, and near the left hand end is a drop down gallery of colour schemes. You can choose to create a new custom colour scheme from the option at the bottom of the list. This will start from the current colours and you can provide your own name for this scheme: "My Funky Colours".

As well as the two light and two dark colours, and 6 accent colours, you will also see the standard colours for hyperlinks and followed hyperlinks. Change these to what you want (possibly the same colour for both, is that what you are trying to get to?) and save your scheme. Job done, and the styles don't need to be changed at all.