boundary
US /ˈbaʊndəri, -dri/
・UK /'baʊndrɪ/
B1
n.NounA division or border to separate two areas
The train route follows the boundary of the city
n.NounIn sports, a line or marker indicating the edge of the playing area.
The ball went over the boundary for a six.
n.NounThe limit of what is known or thought possible.
The research pushes the boundaries of scientific knowledge.