co-trustee
noun[C]
(alsocotrustee)uk/ˌkəʊ.trʌsˈtiː/us/ˌkoʊ.trʌsˈtiː/one of two or morepeopleororganizationswho togethercontrolthepropertyand/ormoneyfor anotherpersonororganization:
She was a co-trusteeofthefund.
- Heservesas co-trustee withclientfamilymembersandfinancialinstitutionson manyaccounts.
 - Generally, you arepermittedtonameanindividual,bank, ortrustcompanyas co-trustee.
 - Hetransferredthe securities to himself and anotherpersonas co-trustees.
 - Cabot's twosisterswere his cotrustees.