As far as I can tell, the word “physics” occurs twice in the Shakespeare canon. Once in The Winter’s Tale, and once in Macbeth. Here’s the latter:
LENNOX Good morrow, noble sir. MACBETH Good morrow, both. MACDUFF Is the king stirring, worthy thane? MACBETH Not yet. MACDUFF He did command me to call timely on him:
I have almost slipp’d the hour.
MACBETH I’ll bring you to him. MACDUFF I know this is a joyful trouble to you;
But yet ’tis one.
MACBETH The labour we delight in physics pain.
This is the door.
Well, I can attest from experience that physics and pain are not entirely unrelated. But that’s not what the bard was actually saying here. Physic was an archaic term approximately meaning medicine. Therefore physics here means something like “medicates”. The labor in which they delight soothes pain. I think so, anyway. I love Shakespeare, but I’m not exactly an expert in the language. It’s Early Modern English from around the year 1600. For comparison even the King James Bible we have today only dates back to 1769.*
So when did the word physics actually start describing physics? This is a subtle question because physics didn’t yet exist at the time of Shakespeare. There were scientists (called natural philosophers then), but the systematic study of the mathematical laws of nature didn’t exist and in fact wasn’t even possible until Newton invented calculus and formulated gravitation in 1687.
According to the Oxford English Dictionary, there were a few references to “physics” - denoting the study of natural science in general - as far back as 1487, but this was both obscure and only vaguely resembling science in its modern sense. A descendant of that old sense of the word survives in the word “metaphysics”. Once Newton got the ball rolling, the both the word physics and the science it describes began to become something like what they were now.
*Originally translated in 1611, it underwent an enormous amount of revision to its spelling, lettering, and punctuation in 1769. If you pick up a King James Bible today, the 1769 text is what you’re reading. The first printings would be more difficult for the average modern reader.