Regardless of the word we use, occasionally there have been times where I was awake but so absorbed in an activity or in my thoughts that I didn’t have a self-experience, for a certain duration (tenths of minutes). My mind was focused solely on the activity, and not on itself whatsoever. It’s a surprising feeling to notice that while you have memory of what you had just been doing, you have no memory of your mind experiencing itself doing it. I would be inclined to say that I wasn’t conscious during that stretch of time.