Bruno Latour is the philosopher behind the title of this wiki. On this wiki we Idea Mine a range of disciplines around the notion that science, law, media and politics can be remixed in new and potentially fruitful ways.
What is a Thing?
A thing is an abstract term. In common parlance, it is a general term we use to refer to an object. The modern meaning takes it's lead from the referential theory of meaning - Wikipedia 
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Interestingly however the original sense of the word "thing" is that of a gathering or political assembly. A Thingstead was an early law court. The meaning of a "thing" in this sense is a political definition, and it would seem by looking at the history of legal terminology, we can see how this softer deliberative meaning, became codified.
Thing as Assembly
Witgenstein famously argued against referentialism, famously saying that "the meaning of a word is its use" - Stanford Encyclopaedia of Philosophy .
A Chose in Action is a Common Law legal definition derived form the French meaning Thing in Action.