Understreking

Understreking is the practice of placing a horizontal line beneath text. The line is used primarily to emphasize a word or phrase, or to indicate a hyperlink in some contexts. In English, the more common term is underlining, and the line is typically positioned a small distance below the baseline, spanning the width of the touched characters.

Historically, underlining arose as a practical method to indicate emphasis in manuscripts and early printed works when italics and other typographic alternatives were less accessible. In the era of typewriters, underlining often served as a substitute for italicization, since the machine’s character set could not easily reproduce slanted type. With the adoption of italic type in modern typography, reliance on underlines for emphasis diminished in print, but the technique persisted in handwriting and annotation.

In digital typography, the underline is implemented through formatting features such as HTML’s underline semantics or CSS text-decoration: underline. On the web, underlines have become closely associated with hyperlinks, which can influence how and when underlining is used for emphasis. Accessibility guidelines advise that emphasis should not rely solely on underlining, and emphasize that links should be clearly distinguishable by multiple cues, not just color or decoration.

Typography considerations for understreking include line thickness, distance from the baseline, and how the underline interacts with descenders in certain fonts. Some designs use variations such as double underlines or colored underlines to convey additional meaning, but these are less common in mainstream typography.

See also: underline (typography), emphasis (typography), hyperlink.