underline

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.

The character _.uncommon

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

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

• Several readers [...] write to point out that the ex-Great Eastern 0-6-0s now classified as "J20" in the L.N.E.R. lists, no longer hold the supremacy for power among British 0-6-0 locomotives as suggested in the underline to the photograph

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

• underline the important words in the text

To emphasise or stress something.figuratively

• The Midlanders will hope the victory will kickstart a campaign that looked to have hit the buffers, but the sense of trepidation enveloping the Reebok Stadium heading into the new year underlines the seriousness of the predicament facing Ow

To influence secretly.figurativelyobsolete

• By mere chance in appearance, though underlined with a providence, they had a full light of the infanta.

Passing under a railway line.not-comparable

• Just as it was sometimes necessary to lower the road to take it beneath an underline bridge, so in this case it might be necessary to raise it.
• A minute was saved by smart working at Ipswich, but soon after came yet another delay, a 10 m.p.h. slack over an underline bridge being reconstructed between Bramford and Claydon.