R 開頭單詞
rareness n.稀罕；珍奇；稀薄
rarely used spare parts [機(jī)械工程]不常用備件[計算機(jī)科學(xué)技術(shù)]不常用備件
rarely seen 很少見到 罕見
rarely if ever 幾乎從不
rarely adv. 很少地；難得；罕有地
rarefying 抽稀
rarefy vt.使變稀少；使變純凈vi.變稀薄=rarify.
rarefies 抽稀
rarefied zone [化學(xué)]稀薄區(qū)
rarefied gas [流] 稀薄氣體
rarefied adj. 高深精妙的，曲高和寡的；遠(yuǎn)離常人生活的，怪異的；（空氣）稀薄的，含氧量低的
rarefication n.稀薄
rarefiable vt.使變稀少；使變純凈vi.變稀薄=rarify.
rarefactor 松弛器
rarefactive adj.稀少的(膨脹的)
rarefactional adj.稀少的(膨脹的)
rarefaction wave [流] 稀疏波；膨脹波；余波