This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
岠 combines 山 (mountain) with 巨 (large), but the exact historical development and original meaning are uncertain. It may have been used as a variant or for a specific place name.
The kanji has no clear meaning, but visually it shows a mountain 山 next to something large 巨. You can imagine a giant mountain, but treat the meaning as unknown.
For キョ, imagine a giant (巨) mountain (山) that everyone calls 'Kyo' — a made-up name that sounds like キョ. The mountain is so large it needs a special name.