waistline Syllabification: (waist·line)Pronunciation: /ˈwās(t)ˌlīn/Translate waistline | into French | into German | into Italian | into Spanish Definition of waistline noun an imaginary line around a person’s body at the waist, especially with respect to its size:eliminating inches from the waistline the shaping and position of the waist of a garment. waistline in other Oxford dictionaries Definition of waistline in the British & World English dictionary