Meaning of “border” - Learner’s Dictionary

border

noun [ C ] us uk /ˈbɔːdər/
They live in a small village near the Danish border.Niagara Falls straddles the Canadian border.The population of the region was swollen by refugees from across the border.Government troops were very thin along the border.Another wave of refugees is arriving at the border.
DIVIDE

B1 the line that separates two countries or states:

the border between France and Spain
We crossed the border from Canada into the US.
EDGE

a strip around the edge of something for decoration:

white plates with a blue border

(Definition of “border noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)