Definition of per my et per tout in US English:

per my et per tout

adverb

Law
  • By joint tenancy; jointly and wholly (so that the whole property passes to the survivor of joint tenants, rather than falling into the deceased tenant's estate, as is the case with a tenancy in common).

Origin

Early 17th century; earliest use found in Edward Coke (1552–1634), lawyer, legal writer, and politician. From Law French per mie et per tout by joint tenancy, lit. ‘of nothing and of all’ (in Anglo-Norman as par my et par tout) from per + mie, negative particle + per + tout all (from classical Latin tōtus: see toto-), after post-classical Latin totum tenet et nihil tenet he holds all and nothing.

Pronunciation

per my et per tout

/pəː ˌmiː eɪ pəː ˈtuː(t)/