olemus
meetrilise ruumi alamhulga H punkt x, mille korral leidub
alamhulgas H sisalduv lahtine kera B(x,r) raadiusega r > 0
=
a point x in a vector space is an internal point of a set B if there is an absorbing set A such that x + A ⊂ B

piltlikult
https://commons.wikimedia.org/wiki/File:Internal_point.svg