An artillery piece, originally a smaller gun that could accompany a field army on the march and when in combat could be moved about the battlefield in response to changing circumstances.

plural of field guide

(algebra, field theory) A field L which contains a subfield K, called the base field, from which it is generated by adjoining extra elements.

plural of field gun

An area of land or seabed where natural gas can be extracted in commercially viable quantities.

plural of field train

(military) A department of the Royal Artillery responsible for the safety and supply of ammunition during war.

(algebra) The quotient ring of a commutative ring divided by one of its maximal ideals; by a certain theorem such a quotient ring must be a field.

(algebra, Galois theory) A subfield of a given field which contains all of the fixed points that are common to all of the automorphisms of some subgroup of the automorphism group of that given field.

A function of all the light flowing through all points of space in a particular volume