The term "physical thing" could refer to a vast array of objects, be it living or non-living. There are several synonyms for this term depending on the context of usage. In the case of non-living objects, "material object," "tangible object," or simply "object," could be more fitting alternatives. If referring to living things, "physical organism," "corporeal being," or "bodily entity," would suffice. Similarly, when referring to specific types of physical objects, you can use "structure," "mechanism," or "system" to describe them. In summary, synonyms for "physical thing" vary depending on the object being referred to. It's important to choose the right synonym to make the description more precise and clear.