by
The air base is bounded by razor wire and high fences.
The resort is located on an island bounded by coral reefs and rocks.
The area was bounded by a main road on one side and a field on the other.
Businesses always seek to lower costs, but this is bounded by supply.

SMART Vocabulary: related words and phrases

Territorial boundaries
border
bound
boundary
bourne
checkpoint
demarcation
frontier
hard border
line of demarcation
no-man's-land
passport control
state line
the Iron Curtain
the Mason-Dixon Line
transboundary
unhedged