diquat

 
Pronunciation: /ˈdʌɪkwɒt/

noun

[mass noun]
  • a synthetic compound used in controlling plant growth, often as a non-persistent contact herbicide.
    • A bromide of a quaternary amine; chemical formula: (C5H4NCH2)2Br2

Origin:

1960s: from di-1 'two' + quaternary