Hello MO, I haven't seen you for a while.
I would take spices (e.g. chilli, turmeric, cumin, coriander seeds) as a subset of seasonings (e.g. salt, herbs, spices).
Possibly there is also a distinction in terms of function. Thus perhaps we could say that spices were originally intended to disguise the flavour of foodstuffs, whereas other kinds of seasoning tend to complement or bring out the flavour. But this may be an unwarranted speculation.