地下
dìxià · HSK 4
underground
⬇️🌍 地 (earth) + 下 (below) = under the ground
地下 literally reads as earth-below. 地 means ground/earth, 下 means below/under. Together they form the word for underground or subterranean — anything located beneath the earth's surface, or done secretly out of sight.
地 — earth 土 + 也 (phonetic)
地 is a semantic-phonetic compound. The left component 土 means 'earth' or 'soil' and gives the meaning, while 也 on the right hints at the pronunciation. Originally referring to the ground or land, it broadened to mean 'place,' 'region,' and 'territory.'
下 — horizontal line 一 + mark below
下 is an indicative character: a long horizontal line represents a reference level, and a shorter stroke placed beneath it points to the area below. The original meaning 'below, down' comes directly from this spatial diagram, and it later extended to verbs like 'descend' and 'lower'.