船便
ふなびん · funabin · JLPT N2 · noun
surface mail
🚢 船 (ship) + 便 (mail): mail sent by ship, the slow and cheap option
Contrast with 航空便 (kōkūbin), airmail: 航空 means aviation, so 航空便 goes by plane and 船便 goes by sea.
船 — boat radical 舟 + 㕣 (phonetic)
船 is a semantic-phonetic compound. The left side 舟 depicts a boat and gives the meaning, while the right side 㕣 originally suggested the sound. Together they refer to a ship or vessel, a meaning that has stayed stable since early seal script.
便 — person 亻 + change 更
A semantic compound: 亻(person) beside 更 (to change/replace). The original sense was a person making things easier or more convenient by adjusting them. From 'convenient' it extended to 'then/thereupon' (biàn) and to bodily 'discharge' (as in 大便).