liner1 Syllabification: (lin·er)Pronunciation: /ˈlīnər/Translate liner | into French | into German | into Italian | into Spanish Definition of liner noun 1 (also ocean liner) a large luxurious passenger ship of a type formerly used on a regular line. 2a fine paintbrush used for painting thin lines and for outlining. a cosmetic used for outlining or accentuating a facial feature, or a brush or pencil for applying this. 3 informalanother term for line drive.liner in other Oxford dictionaries Definition of liner in the British & World English dictionary