far apart; ends of the earth
Yojijukugo meaning two places are extremely distant from each other, like the edge of the sky and the corner of the earth. Literary and somewhat rare.
The two were separated far apart, as if at the ends of the earth.
天涯 alone means 'the edge of the sky' or 'a faraway place', while 天涯地角 emphasizes the extreme distance between two points.
地角 alone means 'the corner of the earth', but it is rarely used independently; it appears mostly in this compound.
A yojijukugo combining 天涯 (edge of the sky) and 地角 (corner of the earth), both classical Chinese expressions for remote places. The exact historical derivation is uncertain, but the phrase is used to emphasize vast distance.