シャッター
シャッター · shattaa · JLPT N2 · noun
shutter
🚪 シャッター = shut + -er: a thing that shuts, like a store's roll-down door
Its sound 'sha-tta' echoes English 'shatter', loosely hinting at a sharp, fast closing. Shops in Japan use it for rolling steel doors over storefronts.