Sentence:  Law is the rule of human conduct. When this term is applied in reference to the governing principles of all actions, inanimate as well as animate, and arising from impulse or necessity, as well as from volition, it is used figuratively, as a <WSD>trope</WSD>, rather than in its true and literal signification—as when we say, the laws of motion, the laws of gravitation, the laws of vegetable or animal life. 
Meaning of the word marked with <WSD> tags:  A figure of speech in which words or phrases are used with a nonliteral or figurative meaning, such as a metaphor.