1.design or provide with a form that presents very little resistance to a flow of air or water, increasing speed and ease of movement."streamlined passenger trains"synonyms:aerodynamic, smooth, sleek"streamlined cars"2.make (an organization or system) more efficient and effective by employing faster or simpler working methods."the company streamlined its operations by removing whole layers of management"synonyms:efficient, smooth-running, well run, slick.