登机口 (dēng jī kǒu) — departure gate

Two or more meaningful parts placed together so that their meanings combine into a new one.

登 pairs 癶, left and right feet, with 豆, a raised object or stepping stone; its older form also showed two hands at the bottom, which later dropped.

Most characters — around four in five — are built this way: one part hints at the meaning, the other at the pronunciation.

The left part is 木 (tree; wood), and the right part 几 gives the sound.

A drawing of the thing itself, worn down over three thousand years into a few strokes.

The form 口 looks like an open mouth.