Does Linux have this as well?
Linux used to have something similar, called TCP low-latency mode, but the flag is no longer functional. Now, there are various distribution specific options or you can rebuild your kernel with multiple related build options to achieve the same.
you can ofcourse do a syscall directly, but i am not sure what value add _that_ is, `man -S 2 syscall` for more information.
edit: 'typically' because some languages / runtimes might go the syscall route.
I suppose though in the context of Linux it's a bit weird, but you did get the correct meaning :).