It's another word for awareness. It depends on information and a drive to map information and navigate it.

I think that there is no hard divide between conscious and unconscious, more like a continuum. All sentient beings are conscious, but maybe not about themselves if the information about themselves doesn't get fed back to them in some way. But they're certainly conscious about their environment to be able to find food.

Consciousness is essential for actions within an environment. Self consciousness isn't essential for learning though, you can learn by doing, like animals. But it's essential for betterment, expanding your options and not relying on the first best thing you've found that worked by doing.

The subjective experience of being.

And if you met me, how would you judge that I'm experiencing what it's like to be me? Is there something like a Turing test for that?

If you believe philosophical zombies are impossible, as many philosophers do, then the Turing test is the consciousness test.

I sort of agree, but human willingness to attribute agency to physical objects (the willingness of the wind to blow, the rains to come, the sun to rise etc.) makes me doubt even quite strong versions of the turing test persay. I'd belive that a robot that managed to live a life in society and could make me feel that it was human like in a conversation was conscious; I think I would want it to have rights and protections.

You've got to think of what a Turing Test conversation would actually look like. See my other comment: https://news.ycombinator.com/item?id=20518623

The experience of color, sound, taste, smell, feels in perception, memory, imagination, dreams and other states of mind.