What is streamlined body?

Answer 1

the shape of many objects moving through air or water is designed in such a way(with pointed ends) that friction can be reduced between the objects and water or air(fluid).The shape of the body is called streamlined body.

Answer 2

This term is used often in the swimming industry or in aquatics. It is relative to the position that the body is in when it is in its most hydrodynamic position parallel but just under the surface of the water. The arms are above the head, hands are stacked and arms squeezing the head at the temples and ears. The chin is slightly tucked towards the chest "suck in your gut, tuck in your butt" legs are long and together and toes are pointed. Thus allowing you to glide in an efficient and "streamlined" position for the least amount of resistance and drag.