streamline (n.) Look up streamline at Dictionary.com
1868, "line drawn from point to point, so that its direction is everywhere that of the motion of the fluid" [Lamb, "Hydrodynamics," 1906], from stream (n.) + line (n.). The adjective is attested from 1898, "free from turbulence," 1907 in sense of "shaped so that the flow around it is smooth."
streamline (v.) Look up streamline at Dictionary.com
1913, "give a streamline form to," from streamline (n.). From 1936 in the extended sense of "simplify and organize." Related: Streamlined; streamlining.