空间 (kōng jiān) 'space' joins 空 and 间. 空 (kōng) means empty and is a phono-semantic compound with the cave radical 穴 over 工 (gōng) for sound. 间 (jiān) means a gap or interval and pictures the sun 日 seen through a gate 门. Together they name empty extent, room or space. The traditional form is 空間.

Origin

compound

Root

空 (kōng, empty) + 间 (jiān, gap/interval)