a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas)
例句
用作名词 (n.)
Helium and neon are inert gases. 氦和氖为惰性气体。
Most big balloons are now filled with helium. 现在许多大气球中充的是氦气。
美
['hiːliəm]
