[pik-luh-ram, pahy-kluh-]
noun Chemistry.
  1. a colorless powder, C6H3Cl3N2O2, used as a systemic herbicide for controlling annual weeds and deep-rooted perennials on noncrop land.

Origin of picloram

1960–65; reverse compound from am(inotrich)lor(o)pic(olinic acid); see amino-, tri-, chloro-2, picolinic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018