\Ces"tuy\ or Cestui \Ces"tui\, pron. [Norm. F.] (Law)
He; the one.
{Cestuy que trust}[norm. F.], a person who has the equitable
   and beneficial interest in property, the legal interest in
   which is vested in a trustee. --Wharton.
{Cestuy que use}[Norm. F.], a person for whose use land,
   etc., is granted to another.