What does underscore mean?
An underscore is a line placed beneath text to emphasize, distinguish, or correct it, and the word can also refer to the underscore character, written _, commonly used in computing and informal writing. As a verb, underscore means to emphasize or highlight something, often with the suggestion that the matter deserves particular attention. The word is especially useful in formal and analytical contexts: a sentence may underscore the importance of a policy, the significance of a result, or the need for a change. It can also describe the physical act of marking a passage with a line below it. In digital communication, the term has become strongly associated with the underscore character used to join words, create readable identifiers, and replace spaces in filenames and web addresses. Although underline is often used as a close alternative, underscore carries the added sense of calling attention to a word or point.
A horizontal line placed beneath a word or passage to emphasize, correct, or distinguish it; also, in computing, the underscore character written as _.
"She drew an underscore beneath the date that needed checking."
The computing sense refers to the character itself, while the traditional sense refers to a line under text.
To emphasize or draw special attention to something, especially by underlining it or treating it as especially important.
"The findings underscore the need for further research."
This is a formal verb and often implies that the emphasized point has particular significance.
The plural refers to multiple lines beneath text or multiple underscore characters.
"The editor added several underscores to highlight the passages requiring revision."
Underscore has traveled from a line beneath words to the quiet little mark that keeps many filenames readable.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does underscore come from?
The word is formed from the prefix under and the word score. In its early use, it referred to a line or mark beneath text, and its modern emphatic sense developed from that marking function. The related word score belongs to the same word family, giving forms such as scorer, scoring, and scored. Its use for the underscore character followed the character’s increasing use in typesetting and computing.
Related word forms
How underscore is actually used
As a verb, underscore is formal and often suggests that a point is especially important or significant. In computing, the term refers specifically to the character _, while underscore as a verb is broader and may mean emphasizing a point without marking the text itself.
Easily confused with underscore
Both can refer to a line beneath text, but underline is the more general word, whereas underscore is especially common in typography and computing for a specific marking character or for emphatic emphasis.