Which part of the celestial sphere does the meridian divide in half non- visible?

The meridian divides the celestial sphere into the northern and southern celestial hemispheres. This imaginary line runs from the north celestial pole to the south celestial pole, effectively splitting the sky into two halves. The portion of the celestial sphere that is not visible to an observer at a specific location is referred to as the "non-visible" or "lower" hemisphere.