Nouns

(n)invasion, encroachment, intrusionany entry into an area not previously occupied“an invasion of tourists”, “an invasion of locusts”
(n)intrusionentrance by force or without permission or welcome
(n)intrusionthe forcing of molten rock into fissures or between strata of an earlier rock formation
(n)intrusionrock produced by an intrusive process
(n)trespass, encroachment, violation, intrusion, usurpationentry to another's property without right or permission