residuum
noun /rɪˈzɪdjuəm/
/rɪˈzɪdʒuəm/
(plural residua
(specialist) /rɪˈzɪdjuə/
/rɪˈzɪdjuə/
)- something that remains after a reaction or process has taken place
（化学反应的）残基，残渣，残留物；（某种进程的）残体 词源late 17th cent.: from Latin, neuter of residuus ‘remaining’, from the verb residere.