秋ㄑㄧㄡqiū毫ㄏㄠˊháo

  1. 鳥獸在秋天所生的細毛。後比喻微細的事物。《呂氏春秋·先識覽·察微》：「察其秋毫，則大物不過。」《儒林外史·第三九回》：「少保傳令，救火安民，秋毫不許驚動。」

英fine hair grown by animals (or down grown by birds)​ in the fall, (fig.)​ sth barely discernible, the slightest thing, the minutest detail