residuum

residuum
[rɪˈzɪdjʊəm]
(pl. residua -djʊə)
  1. (technical)a substance or thing that remains or is left behind, in particular
    (技)残留物,余留物,尤指
    a chemical residue.
    化学残留物。
    ■(Sociology)a class of society that is unemployed and without privileges or opportunities
    (社会学)弱势阶层(指社会上无业、无特权或无机会者)
语源
  1. late 17th cent.: from Latin, neuter of residuus 'remaining', from the verb residere
英语宝典
考试词汇表