Definition
to demarcate an area by placing a boundary around it
划出；隔开
We need to mark off this area for construction.
我们需要把这个区域划分出来进行施工。
She marked off a section of the garden with a rope.
她用绳子把花园的一部分隔开。
For safety, we marked off a perimeter around the quarantine area.
为了安全起见，我们在隔离区周围划定了周界。