1. 无风：calliper 测径器 | calm air 无风 | calm wind 静风

2. 无风 平静大气：callus wood || 愈合材 | calm air || 无风 平静大气 | calm before the storm || 暴风雨前的平静

noun

1. wind moving at less than 1 knot
    0 on the Beaufort scale

    Synonym: calm