A body of knowledge is the accepted ontology for a specific domain. A BOK is more than simply a collection of terms; a professional reading list; a library; a website or a collection of websites; a description of professional functions; or even a collection of information.
A singularity is an infinitely small and infinitely dense point of matter from which the universe came. The big bang theory suggests that the big bang was like a balloon inflating from that infinitely tiny point into the universe we know today. There is plenty of evidence about this.
The greenhouse effect is the trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun