An entry into a place or area that was previously uncommon; an advance beyond former borders; intrusion; incursion.
That which is gained by such unlawful intrusion.
An intrusion upon another's possessions or rights; infringement.
An unlawful diminution of the possessions of another.
An advance into enemy territory, an attempted invasion; an encroachment, an incursion.
Often followed by in, into, or on: initial progress made toward accomplishing a goal or solving a problem.