This is the 2004th most frequent Russian word.
уничтожения
Destruction or annihilation.
'уничтожения' refers to the act of destroying old documents in a context of processing or completing a task.
Процесс уничтожения старых документов занял несколько часов.
The process of destruction of old documents took several hours.
'уничтожения' is used to indicate the aim of an act, in this case, targeting vegetation for destruction.
Последствия использования химического оружия для уничтожения растительности были катастрофическими.
The consequences of using chemical weapons for the destruction of vegetation were catastrophic.
'уничтожения' signifies the purpose of systems being developed, namely to destroy hostile objects.