Also give defination of some words like Alien. Usually alien means living beings (or non-living object) from outside of the Earth. But here I think here alien's meaning is different. Also what is the difference between spirit and soul. Aren't they are synonyms?

From what I understood, from integrated consciousness perspective, alien, human, soul, spirit etc are all it.

I understand the meaning You mean by aliens, such as we in the sea we are alien for the fishs. In the Tctdf for aliens we mean beings from other worlds, and there are physical and non-physical aliens. The spirit and the soul are two different things, the Spirit is male part, the soul is the female part. I suggest you to go read and do directly the TCTDF