The term field is from the Old English feld "plain, pasture, open land, cultivated land" (as opposed to woodland), also "a parcel of land marked off and used for pasture or tillage," probably related to Old English folde "earth, land," from Proto-Germanic *felthan "flat land." As "battle-ground," c. 1300. Meaning "sphere or range of any related things" is from mid-14c. Physics sense is from 1845. 

The battle ground of today can be found in all geographies and industries. Seven continents. Techonology. Energy. Commodities. What fit is your field? What activities will you engage in to achieve desired results? Defining your field is the start of your strategy. 

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Invitation to life, dance with a partner of dreams, wear a tuxedo