Because nonduality has been increasingly popularized in recent years and has always been rather broadly conceived, I'm beginning to think that it would be helpful to, almost always, use the concept with adjectival descriptors, such as: 1) nondual perception (e.g. subject-object negation) or existential nonduality
2) nondual thinking (e.g. transcending the oppositional) or epistemic nonduality
3) nondual ontology (e.g. monism) or metaphysical nonduality
4) nondual emptiness (e.g. relating samsara, nirvana & sunyata, etc) or primordial nonduality
5) nondual experience (e.g. unitary at-one-ment, unitive communion, etc) or mystical nonduality
Different authors variously conceive nonduality, narrowly vs broadly, including or excluding, some of these meanings.
As for the word consciousness, I've resolved to simply despair over what that's supposed to mean, one author vs the next.