If we consult the OED on the word “physical” we find the following as the primary definition: “relating to the body as opposed to the mind—involving bodily contact or activity”. Only the third definition given captures the sense intended by philosophers: “relating to physics or the operation of natural forces generally”. The primary definition might be paraphrased as of the body: to be physical is to involve the human body, to be located in the body, to concern the body—as opposed to the mind, the psyche, the spirit, the soul. This is the sense employed in such locutions as: physical education, physical exercise, physical therapy, physical anthropology, physical abuse, physical appetites, physical examination, physical love affair, and physical beauty. The word “physical” in this use is close to “fleshly”, “somatic”, and “carnal”: to be physical is to consist of (or somehow involve) flesh and bone, blood and guts, muscle and mucous. The organs of the body are physical in just this sense, being precisely organs of the body. The brain is no exception: it is indisputably of the body, one of its parts. The mind, by contrast, is not clearly of the body, which is why it has been deemed immortal, separate from the body, a different kind of thing entirely (not even material). Mark that to be physical in this sense is not to be physical in the sense favored by philosophers: something can be of the body without being fully describable by physics. A vitalist could believe that the organs of the body are not reducible to physics, holding that a special force animates living tissue; or you might think that biological concepts are not reducible to the concepts of physics and chemistry.  We can be quite neutral on the science and metaphysics of the living body while declaring certain things to be of the body—or not of the body, as the case may be. In the past the mind was thought to be not of the body and hence not physical in the present sense: it was deemed immaterial, incorruptible, located elsewhere, not beholden to the body for its existence, and maybe not even causally connected to the body. Thought, in particular, was taken to be non-physical in this sense—not an attribute of the body at all. Thinking is not a bodily process like digestion or breathing : the soul thinks and it is not of the body. Thus we can coherently envisage a doctrine, viewed as radical, that maintains that, contrary to tradition and maybe even common sense, the mind is physical in the sense we are considering: it is of the body. We can call this doctrine “physicalism”, carefully distinguishing it from the doctrine usually so called by philosophers, i.e. the doctrine that the mind is reducible to the entities and properties described by physics. The former doctrine is not hostage to the fortunes of the latter doctrine; indeed, proponents of it might be hostile to that doctrine, viewing it as false, vacuous, or even nonsensical. Being of the body is not to be equated with being as physics describes things, now or in the future: for it may be held, for various reasons, that there is no merit in the idea that the body is purely physical in that sense. In any case, I wish to investigate the former doctrine in its own right: the idea that the mind is really a bodily thing and not a non-bodily thing—which I will call simply “physicalism”. It might also be called “bodyism” or “somaticism”, but the dictionary licenses using the word “physical” to refer to the doctrine in question. Is physicalism in this sense true?
It is important to see what physicalism, as so defined, opposes. Take mental illness: a non-physicalist would hold that mental illness is caused by evil spirits or impure thoughts or developmental factors operating independently of the body (including the brain). It should therefore be treated by a priest or a psychoanalyst not by a neurologist. But a physicalist about mental illness would hold that it has causes within the body of a chemical nature and that the appropriate treatment should be directed at the body (drugs, surgery, physical exercise, etc.). Even if the etiology is psychogenic, the illness itself is connected to the brain in discoverable ways and could not exist without the brain’s cooperation (so to speak). Mental illness is not a condition of an immaterial substance cut off from the body but is deeply enmeshed in the body’s biological activity. Thus we have a physical (bodily) account of mental illness as opposed to a supernatural (non-bodily) account. Note that we are not saying that the psychological manifestations of mental illness are reducible to brain states or facts described by physics; it is just that mental illness is body-involving, body-located, inextricably bound up with the body. Let’s even boldly state that we have discovered this to be true by empirical investigation, whatever may be the case with respect to the reducibility of psychology to physics. In the same way it may be said that mood swings and depression are physical phenomena, being occasioned by chemical imbalances and the like; they are not perturbations of an immaterial spirit lurking somewhere in the general vicinity the body. Ditto for hunger and thirst. Emotions in general might be similarly viewed: they involve the body in various ways—flight, approach behavior, butterflies in the stomach, genital arousal, and so forth. Specific parts of the brain are activated during emotional excitation. Emotions are bodily phenomena not disembodied states of a quasi-divine soul: they have a “physiological basis and origin”, as one dictionary says under “physical”. As for perceptual experiences, the physicalist will assert that they are intimately joined to the bodily sense organs and hence “of the body”: seeing is a physical process because of the bodily eye, as are tasting and smelling because of the mouth and nose. We don’t see, taste, and smell in some way removed from our bodily nature: these are physical processes (even if the sensations involved are not reducible to brain states). They are anchored in the body, dependent on it, shaped by it. Hence physicalism in the present sense is true of emotions.
The case of thought presents more of a challenge to this brand of physicalism, because its bodily connections are not so evident. Here the case for a non-bodily immaterial substance has been at its strongest. This tells us that physicalism of the kind under consideration is not a trivial or empty doctrine—it has polemical bite. It might even be false!  But the determined physicalist is not without resources even in the case of thought: putting aside the existence of regular brain correlates, the physicalist might insist that thought has bodily functions in the shape of behavior, and that it plausibly has an evolutionary explanation that invokes aspects of the organism’s body.  It is the function of thought to control the body’s activity so as to secure the organism’s goals, and thought (it may be suggested) arises from features of the body involved in activity involving the hand and mouth. Evolutionary change builds on prior traits of the organism and thought must have developed from earlier properties of the body—or so it may be contended. So thought is not as disconnected from the body as may appear at first sight: there is thus room for a physicalist account of its origin and function. Thought is physical in the sense that it is of the body and not removed from the body, as religious dogma and dualist metaphysics may require. Logical reasoning, like mental derangement, has its somatic roots, its bodily bedrock, its flesh and blood associations. This is not to say that logical reasoning is reducible to the motions of matter, as the usual kind of physicalism claims; it is just to say that it is connected to the body in significant ways. The mind is thus “of the body” not something existing in splendid isolation from the body, as in traditional forms of supernatural dualism. Its ability to exist in disembodied form is accordingly put into question, making physicalism at odds with religious conceptions. I venture to suggest that we have discovered this to be true by a mixture of empirical investigation and philosophical reflection; and it in no way depends on accepting physicalism in the usual sense intended by philosophers of mind. The two doctrines say completely different things. I would say, then, that the former kind of physicalism is true, uncontroversially so in today’s intellectual climate, while the latter kind of physicalism is not true (or even really intelligible). It is a question whether the attraction of the latter doctrine, such as it is, owes anything to the evident appeal of the former doctrine: some sort of physicalism is true, after all, though not the sort commonly advocated today. Do we hear echoes of the one in the other and mistakenly conclude that it must be true because the other is? And let us note that the dubious doctrine itself makes no explicit reference to the body: it simply announces that mental phenomena can be explained in terms of the concepts developed in physics to deal with the inanimate world—the living body as such is left out of account. Clearly this is an extremely ambitious doctrine going far beyond the relatively anodyne suggestion that the mind is inextricably bound up with the body. Neither form of physicalism entails the other, but both can be expressed using the ambiguous term “physical”–one sense yielding something true, the other sense not so much.
A glance at the history may be helpful. Nineteenth-century science, particularly biological science, made great strides in understanding the body, including the brain. The mind came to be seen as an outgrowth of the body, fostering the doctrine that the mind is really a function of the body.  This superseded older dogmas founded in religion that sought to place the mind in a separate non-bodily realm. The doctrine I am calling “physicalism” was thus firmly established at this time and only confirmed by subsequent study. This intellectual stream is separate from the metaphysical materialism that goes back to Hobbes: that doctrine was never firmly established and, according to some, never will be (for many reasons). I am simply pointing out that the two doctrines labeled “physicalism” are quite different, so that the fate of one does not depend on the fate of the other. We can therefore be “physicalists” without being physicalists—the mind is “of the body” while not being “material” (whatever that means). This seems like a good thing because the thought that the mind is in some sense “physical” is surely correct: yes, it is physical in that it is an attribute of the body, bound up with the body, situated within the body. It is not something existing separately, proceeding by its own power, capable of life without a body. Does this solve the mind-body problem? Not in the slightest: in fact it is what is needed in order to formulate that problem. For the problem is how the mind can relate to the body in which it is so clearly enmeshed—there would be no such problem if the mind were simply ontologically remote from the body. There could be a mind problem if the mind had a separate existence, but there is only a mind-body problem because the mind and the body are somehow stuck together. The brain is of the body by virtue of being literally inside the body and made of the same kind of stuff as it, but the mind is not of the body in that way—so in what way is it of the body? All I am saying here is that there is a form of physicalism, properly so called, that is not the same as the doctrine usually bearing that name. The mind truly is physical, though it is not true that it is part of the subject matter of physics. The mind is physical by being biological (somatic, organic) but not by being covered by the science of physics. The old opposition between being of the body and being of the mind has collapsed, with the mind now also regarded as being of the body. In the beginning was the body (not just the body’s deeds); the mind came along later firmly attached to the body. Thus the mind is as physical as the heart or kidneys in that sense (though not in the other sense). 
 We could be mysterians about the body and yet hold that the mind is physical: the mind is of the body and yet the body is a mystery. I suppose we could even be immaterialists about the body and still believe the mind is physical (bodily)!
 I read somewhere that breathing itself was not always regarded as bodily but viewed rather as an influx of spirits that kept the body alive by supernatural means (or did I dream this?). When the lungs were discovered breathing came to be seen as a bodily function sans spirits.
 From a first-person introspective point of view, the essential involvement of the body in all one’s mental life is by no means apparent, so physicalism in the present sense has some work to do to overcome the deliverances of introspection. It is essentially a theoretical position not one founded in phenomenology; hence it has been a matter of controversy.
 I describe a view like this in Prehension (2017), especially chapter 10.
 I can’t resist mentioning Freud at this point: he is a true physicalist in the present sense because he maps psychological formations onto bodily formations in his theory of the development of the psyche. Thus the oral, anal, and genital stages correspond to psychological maturation: if you want to understand human pleasure, you need to see it as emerging from these parts of the body, according to Dr. Freud. Psychoanalysis proceeds by somatic analysis. Of course, psycho-sexuality cannot be disconnected from bodily organs; it was this connection between sexual appetite and the body that led theologians to seek ways of turning the mind to higher things (up there in the soul not down here in the loins). Sexual desire is unavoidably physical (bodily) desire.
 I don’t think the view I have described here has an accepted label, or is even recognized as a theoretical option, though it evidently exists in the historical record. I have thought it worthwhile to delineate it and distinguish it from other doctrines that are more familiar. And it is nice to be able to report that at least one version of physicalism is actually true!