To form a barrier to something or some area by surrounding or blocking it with (usually brightly colored) tape. A noun or pronoun can be used between "tape" and "off." City regulators have taped the building off ahead of its demolition.Make sure you tape off the crime scene so no one contaminates the evidence before the detectives arrive.
tape off
v.
To restrict or reserve some location or area by encircling it with tape: The police taped off the crime scene. We taped the bench off so that no one would sit on the wet paint.