幕
mù · HSK 7
curtain or screen
🎭 幕 = cloth (巾) under 莫; a stage curtain, and one 幕 is one act counted between curtain rises
The 巾 cloth radical marks 幕 as a hanging curtain or tent; 莫 (mò) lends the sound. A theatre curtain falls between acts, so 幕 became the measure word for acts or events in a performance.
幕 — grass 艹 + sun 日 + big 大 + cloth 巾
Originally a semantic-phonetic compound: 莫 (mù, sunset/dusk) provides the sound and the idea of evening, while 巾 (cloth) gives the meaning. It depicted a cloth hung at dusk, hence 'curtain' or 'tent,' later extended to 'act/scene' in a play.