開通
かいつう · kaitsuu · JLPT N2 · noun
opening
🚪 開 = open + 通 = pass through: a door opened so people can pass through
Used when a service, line, or account is switched on, such as a new phone line being activated. The 通 part means connected or passed through.
通 — 辵 (辶) walk + 甬 yǒng (phonetic)
通 is a semantic-phonetic compound. The 辶 (chuò) component means 'walk' or 'movement', giving the meaning of going through or passing. 甬 (yǒng), originally depicting a hanging bell or a path, supplies the sound. Together they convey 'to pass through, communicate, connect'.