Field lacrosse is a full contact outdoor sport played with two opposing teams of ten players each. The sport originated among Native Americans, and the modern rules of field lacrosse were initially codified by Canadian William George Beers in 1867. Field lacrosse is one of three major versions of lacrosse played internationally. The rules of men's lacrosse differ significantly from women's field lacrosse. The two are often considered to be different sports with a common root. An outdoor six-a-side version, lacrosse sixes, was established in 2021 and features six players per team, reduced field size, and shorter duration to be conducive for daily tournament play. Another version, indoor box lacrosse, is also played under different rules.

Lacrosse is a contact team sport played with a lacrosse stick and a lacrosse ball. It is the oldest organized sport in North America, with its origins with the indigenous people of North America as early as the 12th century. The game was extensively modified by European colonists, reducing the violence, to create its current collegiate and professional form.