JEJUNUM   :   

The mid-section of the small intestine of many higher vertebrates like mammals, birds, reptiles is called as jejunum. It is present between the duodenum and the ileum.

JET STREAM   :   

Fast flowing, relatively narrow air currents found in the atmosphere at around 11 kilometres (36,000 ft) above the surface of the Earth, just under the tropopause.

JOVIAN PLANET   :   

Any of the four outer, gaseous planets: Jupiter, Saturn, Uranus, and Neptune.

JUNCTION (CELL)   :   

A protein based structure that connects two adjacent cells. Junctions are used for contact formation and communication. Common junctions in animal systems are tight junctions, gap junctions, desmosomes and hemidesmosome (connects a cell to the extra-cellular matrix to form stable connective tissue).