Sentence:  magnetic <WSD>field</WSD>;  gravitational <WSD>field</WSD>;  scalar <WSD>field</WSD> 
Meaning of the word marked with <WSD> tags:  (physics: region affected by a particular force)  A physical phenomenon (such as force, potential or fluid velocity) that pervades a region; a mathematical model of such a phenomenon that associates each point and time with a scalar, vector or tensor quantity.