x1 is a black hole/singularity with radius of event horizon x2
This is a word based on the cultural idea of a black hole, and so contains places of cultural importance, rather than the physical characteristics that define a black hole. It is a shortening of kensa jipno se farlu into a 2 derived from word(s) x3">jbofuvi. See gramykemjipselfa'u, xekyke'a.