underlineTranslate underline | into French | into German | into Italian | into Spanish Definition of underline verb Pronunciation: /ʌndəˈlʌɪn/ [with object] draw a line under (a word or phrase) to give emphasis or indicate special type: certain phrases had been underlined emphasize (something):the improvement in retail sales was underlined by these figures noun Pronunciation: /ˈʌndəlʌɪn/ 1a line drawn under a word or phrase, especially for emphasis: sub-headings have an underline in blue 2the line of the lower part of an animal’s body: she has a white tail and underlineunderline in other Oxford dictionaries Definition of underline in the US English dictionary