洞 (dòng): cave; cavern

Meanings

氵(water) + 同 (same/through) — an opening water flows through

Shān shàng yǒu yī ge dà dòng.

There's a big cave on the mountain.

Qiáng shàng yǒu yī ge xiǎo dòng.

There's a small hole in the wall.

Biānfú zhù zài shāndòng lǐ.

Bats live in caves.

Wàzi pò le yī ge dòng.

There's a hole in the sock.

usage

Common compounds: 山洞 (shāndòng, cave), 洞穴 (dòngxué, cavern), 黑洞 (hēidòng, black hole), 漏洞 (lòudòng, loophole).

洞 dòng