通宵
tōng xiāo · HSK 7
all night
🌙 通 = throughout + 宵 (night) = all the way through the night
宵 means night; 通 here means to go through or all the way. Put together, 通宵 = right through the night without sleeping. Pronounced tōng xiāo, the 宵 sounds like shyaow and is the same 宵 in 元宵 (Lantern Festival night).
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'.