I'm studying engineering and there's a physics teacher that strikethroughs the derivative $d$ when writing an expression for power (which is work over time). I know physics teachers are known to abuse mathematical notation, but this intrigued me as I had never seen it used and couldn't find anything online. So the expression she writes is:
$đW/dt = ...$
What does it mean for the $d$ to be struck like this?
I've seen this frequently in physical chemistry books. It's to remind you that this is an inexact differential that results in a path-dependent integral. So, for example, it would be used with $dq$ or $dw$, but not with $dE$ or $dS$. They call $E$ and $S$ state variables, but $q$ and $w$ are really not well-defined functions — they depend on the path/process, not just on the endpoints.