Jogging is a form of trotting or running at a slow or leisurely pace. The main intention is to increase fitness
Fitness may relate to:* Physical fitness, a general state of good health, usually as a result of exercise and nutrition * Cardiorespiratory fitness...

 with less stress on the body than from faster running.
The definition of jogging as compared with running is not standard. Dr. George Sheehan
George A. Sheehan
Dr. George A. Sheehan was born in Brooklyn, New York. He is best known for his books and writings about the sport of running. His book, "Running & Being: The Total Experience," became a New York Times best seller. He was a track star in college, and later became a cardiologist like his father...

, a running expert, is quoted to have said "the difference between a jogger and a runner is an entry blank". Mike Antoniades offers a more specific definition, describing jogging as running slower than 6 mph (10 minute per mile pace, 9.7 km/h, 6.2 min/km).
In 1593 William Shakespeare
William Shakespeare
William Shakespeare was an English poet and playwright, widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's national poet and the "Bard of Avon"...

 wrote in Taming of the Shrew, "you may be jogging whiles your boots are green"; the word green meaning 'new', thus, jog when you are fresh, or when you are most ready or able.

The etymology of the word jog is unknown, but it may be related to shog or be a new invention in the sixteenth century.