Definition of "underline" in English

noun

1. A line placed underneath a piece of text in order to provide emphasis or to indicate that it should be viewed in italics or (in electronic documents) that it acts as a hyperlink.

2. (uncommon) The character _.

3. (dated) An announcement of a theatrical performance to follow, placed in an advertisement for the current one.

4. (dated) A caption beneath a photograph (which may have more than one line of text).

verb

1. To draw a line underneath something, especially to add emphasis.

   • underline the important words in the text

2. (figuratively) To emphasise or stress something.

3. (figurative, obsolete) To influence secretly.

adjective

1. Passing under a railway line.