Properly speaking, though, the streamline is a very precise scientific idea. It is a situation where the direction of any given particle moving past a surface is equal to the tangent of the curve of the surface at that point.
A tangent is, of course, a straight line that touches (tangibly) a curve (as in the picture at the top right). So if an object is of just the right shape and put in a stream in just the right place it will have a minimal deflection of the flow.
The word streamline was invented in 1868 and spent the next 65 years as a proper scientific term, appearing only in stern academic papers on inviscid fluid, until it was taken out one night by the poet Stephen Spender, who got the word drunk, took her honour from her, and included her in a bit of a poem about sunset. Now, shamed and denuded of her original sense, she is, I'm afraid, in business.
The Inky Fool has a new car


This suggestive little phrase originally meant opening the books, or providing additional information about a company, to an outsider - typically a potential investor, employee, merger partner, acquirer. But it is also used as