Definitions:
an area of open land, especially one planted with crops or pasture, typically bounded by hedges or fences

a particular branch of study or sphere of activity or interest

a space or range within which objects are visible from a particular viewpoint or through a piece of apparatus.

all the participants in a contest or sport

an area on a flag with a single background colour

the region in which a particular condition prevails, especially one in which a force or influence is effective regardless of the presence or absence of a material medium.

a system subject to two binary operations analogous to those for the multiplication and addition of real numbers, and having similar commutative and distributive laws.

attempt to catch or stop the ball and return it after it has been hit by the batter, thereby preventing runs being scored or base runners advancing.

send out (a team or individual) to play in a game

deal with (a difficult question, phone call, etc.).

carried out or working in the natural environment, rather than in a laboratory or office