References in common literature ? I gave the heap a shove about the lip with the entrance. The subsequent second there came up from below a howl of rage. encroachment, intrusion, invasion - any entry into an area not Earlier occupied; "an invasion of travelers"; "an invasion of locusts" space, https://entrance-mats57899.tinyblogging.com/the-2-minute-rule-for-entrance-mats-81728160