Noun
(ecology) The (typically inadvertent) dispersal of seeds, spores, or other reproductive botanical material, or of reproductively capable animals, by humans as a routine means of reproductive dispersal of that species.
(ecology) The (typically inadvertent and sporadic) dispersal by humans, of seeds, spores, or other reproductive botanical material, or of reproductively capable animals, into a region where they do not natively occur, resulting in adventitious anthropochorous establishment of an alien population if successful.
Source: en.wiktionary.org