Meaning of “border” - Learner’s Dictionary

border

noun [ C ] uk us /ˈbɔːdər/
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)