一卡通
Yī kǎ tōng · HSK 7
card
💳 一 (one) + 卡 (card) + 通 (pass through) = one card passes through all the gates
Beijing's transit smart card: 一卡 is one card, 通 means to go through or connect. One tap and the turnstile opens, so a single card works across buses and subway.
一 — single horizontal stroke
一 is one of the simplest pictographs in Chinese, depicting a single horizontal line to represent the number one. It has retained essentially the same form since oracle bone script over 3,000 years ago. By extension it also means 'first,' 'whole,' or 'same.'
卡 — 上 (up) + 下 (down)
卡 is a modern compound formed by stacking 上 'up' on 下 'down', visually depicting something stuck between two positions — neither up nor down. From this 'wedged' image come its core meanings: to block, to get stuck, and a checkpoint or card. The reading kǎ also transcribes foreign words like 'card', while qiǎ keeps the older 'pinch/stuck' sense.
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'.