What is the difference between exercise, training, practice, sport, and physical activity?

According to "The Oxford Dictionary of Sport Science and Medicine"

Exercise =
1. Human movements and physical activities which involve the use of large muscle groups rather than highly specific, relatively non-taxing movements of small muscle groups. It includes dance, calcithenics, games, and more formal activities such as jogging, swimming, and running.
2. Any set of movements designed to train to improve a skill

Training =
An exercise programme designed to assist the "learning of" skills, to improve physical fitness and thereby to prepare an athlete for a particular competition. It includes "conditioning, specific technical training, and psychological preparation.

Practice =
The repetition of techniques and skills, often taken out of the context of a whole game or event, so that they may be improved.

Sports =
Any highly structured, goal directed physical activity governed by rules, which has a high level of commitment, takes the form of struggle with oneself or involves competition with others, but which also has some of characteristics of play. It involves either vigorous physical exertion or the use of relatively complex physical skills by individuals whose participation is motivated by a combination of intrinsic satisfaction associated with the activity itself and the external rewards carned through participation.

Physical activity =
Exercise and general movementthat a person carries out as a part of their day (http://www.sportsmedicinedictionary.com
)