bona vacantia

/B OW1 N AH0 V EY0 K AE0 N SH AH0/
noun
  1. 1

    The principle that there is no unowned property, and that if there is no other owner then property vests in the Crown.

    โ€œ"The company asked also for an express vesting order concerning the land, which had legally gone to the Crown as bona vacantia" http//books.google.co.uk/books?id=WvY3AAAAIAAJ&pg=PA814&dq=bona+vacantiaโ€

Source: https://en.wiktionary.org/wiki/bona%20vacantia